Overweight: Definition, Health Risks, and What You Need to Know

Overweight is not just an issue of appearance; it is a condition that significantly increases the risk of various health problems. It refers to a state where excess fat accumulates in the body, not merely having a high weight. In Japan, the prevalence of overweight and obesity is on the rise due to changes in diet and lack of exercise. It is crucial to have accurate knowledge about whether you are considered overweight and how it might affect your future health. This article explains the precise definition, criteria, causes, health risks, and practical measures you can take starting today to address overweight. We hope this information will contribute to maintaining your health.

What is Overweight? Definition and Medical Criteria

While the term "overweight" is commonly used in daily conversation, a more precise definition and set of criteria exist in medicine. These are important for objectively evaluating an individual’s health status and determining necessary medical interventions.

BMI Criteria for Overweight

Both internationally and in Japan, Body Mass Index (BMI) is primarily used to classify overweight and obesity. BMI is a simple index calculated from height and weight, indicating how much body mass you have relative to your height.

BMI = Weight (kg) ÷ (Height (m) × Height (m))

For example, for a person weighing 70 kg with a height of 175 cm (1.75 m), the BMI is 70 ÷ (1.75 × 1.75) = 70 ÷ 3.0625 ≈ 22.86.

The Japan Society for the Study of Obesity’s classification of adult body weight based on BMI is as follows:

BMI Category (Japan Society for the Study of Obesity)	Classification	Health Risk (General Tendency)
Less than 18.5	Underweight	High (Nutritional deficiencies, illness, etc.)
18.5 to less than 25	Normal Weight	Standard
25 to less than 30	Pre-obese (Overweight)	Slightly High
30 to less than 35	Obesity Class I	High
35 to less than 40	Obesity Class II (Severe Obesity)	Very High
40 or greater	Obesity Class III (Severe Obesity)	Very High
40 or greater and having obesity-related health problems	Obesity Class IV (Morbid Obesity)	Very High

As the table shows, a BMI of 25 or greater is the medical starting point for "overweight." Many studies indicate that health risks such as high blood pressure and diabetes begin to increase even in the "pre-obese (overweight)" category (BMI 25 to less than 30). "Obesity Class I" (BMI 30 or greater) is a state with further elevated health risks, often requiring medical management and treatment.

How to Calculate and Utilize BMI

Knowing your BMI is the first step in health management. In addition to the formula above, many websites and health apps offer BMI calculators, making it easy to determine your current status.

If your BMI is classified as high, it suggests not just that you are overweight, but also that you may be at increased risk for health problems. Regularly checking your BMI and confirming whether your body weight is within a healthy range provides an opportunity to re-evaluate your lifestyle. However, as mentioned earlier and discussed further below, BMI alone may not always be sufficient for accurate assessment.

Why BMI May Not Always Be Sufficient

BMI is calculated solely from height and weight, and thus does not consider the body’s composition, specifically the balance between "body fat" and "lean body mass" (muscle, bone, water, etc.). This is a limitation when using BMI alone to determine overweight status.

• Individuals with High Muscle Mass: Athletes and bodybuilders with a lot of muscle mass tend to be heavy relative to their height. As a result, they may have a high BMI despite having a low body fat percentage and a healthy body composition. A high BMI in these cases does not necessarily mean they are "overweight" with associated health risks.
• Sarcopenic Obesity in Older Adults: As people age, muscle mass tends to decrease due to aging and reduced physical activity, while body fat percentage may increase. This condition is called "sarcopenic obesity." Even if the BMI is within the normal range, increased body fat and decreased muscle mass can raise the risk of functional decline and metabolic abnormalities. Sarcopenic obesity can be overlooked when relying solely on BMI.
• Hidden Obesity: This refers to a state where BMI is within the normal range, or even underweight, but body fat percentage is higher than standard. Particularly, individuals who appear thin but have excess visceral fat are referred to as having "hidden obesity," and they are known to be at high risk for lifestyle-related diseases.
• Body Fat Distribution: From a health risk perspective, where body fat is stored is also important. "Visceral fat," which accumulates around internal organs, is more likely to cause metabolic abnormalities and is associated with higher health risks compared to subcutaneous fat. BMI alone does not provide information about the amount of visceral fat.

For these reasons, a comprehensive assessment that includes BMI, waist circumference measurement, and body composition analysis (body fat percentage, muscle mass) using a body composition scale is recommended for accurate evaluation of overweight status.

Main Causes of Overweight

Overweight and obesity are rarely caused by a single factor; rather, they are typically the result of a complex interplay of various factors. Fundamentally, they occur when the balance between energy intake (calories) and energy expenditure is disrupted, leading to "Intake > Expenditure" and the accumulation of body fat.

Dietary Habits

The modern food environment tends to promote overweight.

• Increased Consumption of High-Energy Density Foods: Frequent consumption of foods that are high in calories even in small amounts, such as pastries, fried foods, fast food, and snacks, is increasing. These foods tend to be high in sugar and fat and do not provide sustained satiety.
• High-Carbohydrate Foods and Beverages: Sugars contained in soft drinks, juices, sweetened coffee, and sweets are quickly absorbed, causing rapid spikes in blood sugar levels and leading to excessive insulin secretion. This can promote fat accumulation and may even increase appetite.
• Irregular Meals: Habits like skipping breakfast, eating large meals at lunch or dinner to compensate, or eating late at night can disrupt the body’s internal clock and make energy metabolism inefficient. The body tends to conserve energy and store fat in preparation for perceived starvation.
• Eating Too Quickly: The brain takes time to register fullness. Eating quickly can lead to consuming large amounts of food before the satiety center is stimulated. Chewing food properly aids digestion and absorption and is important for feeling appropriately full.
• Habitual Snacking: Unnecessary snacking significantly increases total calorie intake. "Emotional eating," or eating out of habit or to cope with stress rather than true hunger, can also be a cause.

Lack of Physical Activity

Reduced physical activity decreases energy expenditure, directly contributing to overweight.

• Sedentary Lifestyle: Spending a large part of the day sitting, such as in desk jobs or extended periods of screen time at home, drastically lowers energy expenditure.
• Technology’s Advance: The widespread use of elevators, escalators, cars, and public transportation has reduced opportunities to walk or move around.
• Lack of Exercise Habits: Without a conscious habit of exercising, it becomes difficult to ensure sufficient energy expenditure through daily activities alone. Muscle mass is likely to decrease, and basal metabolism (energy expenditure at rest) also tends to decline.

Lifestyle Habits (Lack of Sleep, Stress, etc.)

While often overlooked, daily lifestyle habits other than diet and exercise are deeply involved in overweight.

• Lack of Sleep: Chronic sleep deprivation is known to disrupt the balance of hormones that regulate appetite. The appetite-stimulating hormone "ghrelin" increases, while the appetite-suppressing hormone "leptin" decreases. This is known to increase appetite, particularly the craving for high-calorie foods.
• Stress: Chronic stress leads to excessive secretion of the stress hormone "cortisol" from the adrenal cortex. Cortisol increases appetite and promotes fat accumulation, especially in the abdominal area. Stress itself can also trigger inappropriate eating behaviors like binge eating.
• Smoking: While some theories suggest smoking suppresses appetite, studies report that smokers are less likely than non-smokers to have healthy eating habits and exercise routines, consequently making them more prone to weight gain. Furthermore, weight gain is common after quitting smoking.
• Excessive Alcohol Consumption: Alcohol itself is high in calories (about 7 kcal per gram) and is sometimes referred to as "empty calories" (high in calories but low in nutrients). Moreover, because alcohol metabolism takes priority, the breakdown of fats from co-consumed food is delayed, making it easier for them to be stored as body fat. Drinking can also increase appetite and lower inhibitions, making it more likely to consume high-calorie foods.

Genetic Factors

Genetics is also a factor that contributes to weight gain, but its influence is generally considered less significant than that of lifestyle habits. It is suggested that individuals with certain genetic types may have differences in energy metabolism efficiency or variations in the mechanisms of appetite and satiety sensation. For example, genes referred to as "obesity genes" have been identified, but possessing these genes does not guarantee obesity, as environmental factors (diet and physical activity) play a significant role. If many family members are overweight, there may be a genetic predisposition, but it is highly likely that shared eating and lifestyle habits among family members contribute more significantly to the tendency to gain weight. Instead of giving up due to genetics, it is important to understand your predisposition and use it as motivation to adopt healthier lifestyle habits.

Other Factors (Medication-Induced, etc.)

Rarely, weight gain can be caused by side effects of certain medications or by diseases involving hormonal imbalances.

• Medication-Induced Obesity: Some medications can cause weight gain due to effects such as increased appetite, decreased metabolism, or fluid retention. Examples include corticosteroids, some antipsychotic and antidepressant medications, certain diabetes medications (insulin, sulfonylureas, etc.), antihistamines, and beta-blockers. If you start gaining weight while taking these medications, it is crucial to consult the prescribing doctor instead of stopping the medication on your own, as they can advise on alternative medications or strategies to manage weight gain.
• Endocrine Disorders: Diseases involving hormonal imbalances can cause weight gain. For instance, hypothyroidism, where the thyroid gland produces insufficient thyroid hormones, leads to decreased metabolism and makes weight gain easier. Cushing’s syndrome, characterized by excessive cortisol secretion from the adrenal glands, typically causes central obesity (fat accumulation around the abdomen with thin limbs), moon face (round face), and other symptoms. Polycystic Ovary Syndrome (PCOS) in women involves imbalances in female hormones and can be associated with weight gain and obesity. If these conditions are suspected, examination and treatment by a specialist are necessary.

Overweight typically results from a combination of these factors. Identifying the specific causes of your overweight and addressing them one by one is key to effective management.

Health Risks and Symptoms Caused by Overweight

Overweight, particularly abdominal obesity characterized by excess visceral fat accumulation, is known to dramatically increase the risk of various diseases, far beyond mere cosmetic concerns. These health problems are collectively recognized as "obesity-related health disorders" or "metabolic syndrome," and if left unaddressed, they can reduce Quality of Life (QOL) and even impact life expectancy.

Below, we detail the main health risks caused by overweight, along with their mechanisms and related symptoms.

Health Risk	Associated Mechanism and Symptoms with Overweight
Diabetes Mellitus (mainly Type 2)	Abnormal secretion of physiological substances (adipokines) from fat cells and chronic inflammation interfere with the function of insulin, the hormone that lowers blood sugar (insulin resistance). Initial stages may be asymptomatic, but progression leads to symptoms like thirst, frequent urination, and fatigue. If left untreated, it can cause serious complications such as retinopathy, nephropathy, and neuropathy.
High Blood Pressure (Hypertension)	Secretions of substances that raise blood pressure from fat cells, promotion of sodium and water reabsorption in the kidneys due to insulin resistance, and activation of the sympathetic nervous system all contribute to increased blood pressure. Initial stages may be asymptomatic, but headaches, stiff shoulders, and dizziness can occur. It is a major cause of heart attack and stroke.
Dyslipidemia (Abnormal Cholesterol/Lipids)	Increased visceral fat leads to excessive synthesis of bad cholesterol (LDL) and triglycerides in the liver, while good cholesterol (HDL) decreases. This also promotes atherosclerosis and increases the risk of cardiovascular diseases. Symptoms are usually absent.
Cardiovascular Diseases	Atherosclerosis (hardening and narrowing of blood vessels) progresses due to the combined effects of overweight-related high blood pressure, dyslipidemia, and high blood sugar. This increases the risk of myocardial infarction (heart attack), angina pectoris (chest pain due to narrowed coronary arteries), and heart failure. Symptoms include chest pain and shortness of breath.
Stroke	Similar to cardiovascular diseases, atherosclerosis in brain blood vessels occurs, increasing the risk of cerebral infarction (blockage) and cerebral hemorrhage (bleeding). Symptoms include sudden paralysis, slurred speech, and impaired consciousness.
Sleep Apnea Syndrome (SAS)	Fat accumulation around the neck, tongue, and airway makes the airway narrower or blocked during sleep. This leads to repeated episodes of interrupted breathing (apnea) during sleep. Symptoms include daytime sleepiness, snoring, and morning headaches, and it increases the risk of high blood pressure and cardiovascular diseases.
Joint Strain	Increased body weight puts excessive pressure on weight-bearing joints such as knees, hips, ankles, and the lower back. This makes it more likely to develop osteoarthritis, where joint cartilage wears down, leading to pain and limited movement. Lower back pain is also a common symptom.
Fatty Liver	A condition where excess fat accumulates in the liver. Non-alcoholic fatty liver disease (NAFLD), which is not due to excessive alcohol consumption, is strongly associated with overweight and can progress to liver cirrhosis or liver cancer if left untreated. It is typically asymptomatic in the early stages.
Gallstones	Overweight, especially rapid weight loss, can disrupt the balance of bile components (particularly cholesterol), making gallstones more likely to form. Symptoms may include pain in the upper right abdomen or back pain.
Certain Cancers	Overweight has been shown to increase the risk of several cancers, including colorectal cancer, breast cancer (especially in postmenopausal women), endometrial cancer, pancreatic cancer, liver cancer, kidney cancer, and esophageal adenocarcinoma. Hormonal changes, chronic inflammation, and insulin resistance are thought to be involved.
Infertility and Menstrual Irregularities	In women, overweight can cause hormonal imbalances leading to ovulatory dysfunction and infertility, irregular menstruation, and polycystic ovary syndrome (PCOS). It can also affect hormone balance and increase the risk of erectile dysfunction (ED) in men.
Pancreatitis	Severe obesity and associated hyperlipidemia can increase the risk of acute pancreatitis. Symptoms include severe abdominal pain.
Mental Health Problems	Overweight and obesity can be a source of mental burden due to body image issues, social isolation from bullying or prejudice, and reduced self-esteem. They are also associated with an increased risk of depression, anxiety disorders, and eating disorders (especially binge eating).

Thus, overweight can affect various organs throughout the body and is a potential root cause of many diseases, either causing them or making them worse. To avoid these health risks, it is critically important to improve overweight status and maintain a healthy weight.

Diagnosis Methods for Overweight

To understand the degree of risk associated with your overweight status and determine what measures are necessary, an accurate diagnosis by a medical professional, not just self-assessment, is essential. Doctors evaluate body status from various perspectives, not just BMI.

Evaluation Methods Other Than BMI (Waist Circumference, Body Composition, etc.)

In medical settings, in addition to BMI measurement, the following methods are used to gain a more detailed understanding of body status:

• Waist Circumference Measurement: This is a crucial indicator for estimating the amount of visceral fat, which is most strongly associated with lifestyle-related diseases. It is typically measured around the navel while standing and exhaling lightly. If this measurement exceeds the Japanese standard (85 cm or more for men, 90 cm or more for women), it suggests suspected visceral fat accumulation and an increased risk of metabolic syndrome.
• Body Composition Analysis: Using a body composition scale or bioelectrical impedance analysis, body fat percentage, muscle mass, visceral fat level, etc., are measured. This allows for the detection of "hidden obesity" (high body fat percentage despite normal BMI) or "sarcopenic obesity" in older adults, as well as the distribution of body fat, which cannot be determined by BMI alone. Regular measurements can also serve as an indicator to track progress in diet and training.
• Blood Tests: Blood tests measure values such as blood sugar (fasting glucose, HbA1c), lipids (total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides), liver function (AST, ALT, γ-GTP), kidney function (creatinine), and uric acid levels. These help evaluate the presence and severity of overweight-related complications (diabetes, dyslipidemia, hyperuricemia, fatty liver, etc.). Thyroid function and certain hormone levels may also be measured to check if an underlying disease is causing weight gain.
• Blood Pressure Measurement: High blood pressure is a complication closely associated with overweight. Accurate blood pressure measurement confirms the presence or absence of hypertension.
• Other Tests: If necessary, tests such as electrocardiogram (ECG) or abdominal ultrasound may be performed to examine the condition of organs like the heart, liver, and kidneys in detail. If sleep apnea syndrome is suspected, a simplified polysomnography may be performed.

Importance of Diagnosis by a Doctor

By comprehensively evaluating these factors, a doctor can accurately diagnose how much your overweight status is affecting your health, what complications exist, and whether there is a hidden underlying disease causing the weight gain.
The greatest benefit of getting a diagnosis from a doctor is receiving personalized advice based on scientific evidence regarding the safest and most effective weight loss methods and treatment plans for you. Relying solely on information from the internet or self-guided methods carries the risk of choosing methods that are not suitable for your body type or health condition, or even harming your health.
Especially if your BMI is 25 or higher, we strongly recommend consulting your primary care physician or a doctor specializing in obesity. The doctor can help you set realistic and sustainable goals, taking into consideration your lifestyle and values. They can also provide appropriate advice and psychological support for various issues that may arise during the weight loss process (e.g., plateaus, dietary concerns, difficulty maintaining exercise). While overweight is often perceived as "self-inflicted," seeking professional support as a medical issue is the most certain path to regaining and maintaining a healthy body shape.

Measures and Prevention for Overweight

To resolve overweight and maintain a healthy weight, it is essential to build a healthy lifestyle that can be sustained long-term, rather than pursuing temporary "diets." Finding methods that you can engage with without undue stress and with enjoyment is key to success.

Basics of Dietary Therapy

Diet is the cornerstone of weight management. Not just the quantity, but also the quality and balance of food are crucial.

• Calorie Control: The basic principle for weight loss is to consume fewer calories than you expend. Start by recording your current food intake to understand your calorie consumption. Generally, reducing calorie intake by about 300-500 kcal per day is a manageable starting point, potentially leading to a weight loss of about 0.5-2 kg per month. Extreme calorie restriction (e.g., below 1000 kcal per day) should be avoided as it can lead to nutrient deficiencies and rebound. It’s important to consult a doctor or registered dietitian to set an appropriate calorie target tailored to your age, sex, and activity level.
• Improving Nutritional Balance: It’s important to consume carbohydrates, proteins, and fats (macro-nutrient balance) in appropriate ratios, along with vitamins, minerals, and dietary fiber.
  • Carbohydrates: Aim for about 50-60% of total energy. Reduce refined carbohydrates like white rice, white bread, and sugary foods, and choose complex carbohydrates rich in dietary fiber, such as brown rice, whole wheat bread, buckwheat noodles, oatmeal, and root vegetables.
  • Protein: Aim for about 15-20% of total energy. Protein is important for maintaining muscle mass and providing satiety. Consume lean proteins like chicken breast, fish, eggs, soy products (tofu, natto), and dairy products with each meal.
  • Fats: Aim for about 20-25% of total energy. Reduce saturated and trans fats found in fatty meats, butter, cream, and fried foods. Consume healthy unsaturated fats in moderation, found in fish (DHA, EPA), olive oil, flaxseed oil, and nuts.
  • Vitamins, Minerals, and Dietary Fiber: Eat plenty of vegetables, mushrooms, seaweed, and fruits. These are low in calories and also help maintain normal bodily functions and enhance satiety. Dietary fiber is particularly important.
• Eating Habits:
  • Eat three meals a day at regular times as much as possible. Especially avoid skipping breakfast.
  • Chew slowly and thoroughly. Chewing about 30 times per bite can help you feel full sooner.
  • "Vegetable First": Eating foods rich in dietary fiber like vegetables, mushrooms, and seaweed first can help control rapid blood sugar spikes and prevent overeating.
  • Limit snacking, or if you must snack, choose small amounts of nutrient-dense options (e.g., nuts, fruits, yogurt).
  • Be mindful of calories from liquids like soft drinks, sweetened coffee, and juices. Water and tea are generally the best choices.

Effective Exercise Methods

Exercise not only increases energy expenditure but also helps maintain and increase muscle mass, boosting basal metabolism, which is important for preventing rebound.

• Aerobic Exercise: Effective for burning fat and improving cardiorespiratory fitness. Examples include walking, jogging, swimming, cycling, dancing, and aerobics. Aim for a total of 150 minutes or more of moderate-intensity aerobic exercise (slightly breathless pace) per week. Choose methods that are easy to continue, such as 30 minutes five times a week, or 20 minutes daily.
• Strength Training: Increases muscle mass and elevates basal metabolism, making your body more resistant to weight gain and easier to lose weight. Bodyweight exercises like squats, push-ups, sit-ups, and lunges, or training with dumbbells or machines. Aim for 2-3 sessions per week, focusing on major muscle groups (legs, chest, back, etc.).
• Flexibility Exercises/Stretching: Stretching before and after exercise helps prevent injuries and aids recovery. Maintaining flexibility is also important for ease of movement in daily life.
• Increasing Daily Activity: Consciously increase opportunities to move your body in everyday life, such as taking the stairs instead of the elevator, walking one train station, stretching during breaks or while watching TV, and actively doing housework. Even reducing sedentary time and increasing time spent standing or walking can increase energy expenditure.
• Tips for Continuing Exercise: If you dislike exercising alone, try doing it with family or friends, or join a gym or local exercise class. Setting small goals and celebrating achievements can help maintain motivation. Keeping a record is also effective.

Improving Lifestyle Habits

In addition to diet and exercise, the following lifestyle habits significantly impact weight management and overall health.

• Ensuring Sufficient Sleep: Aim for 7-8 hours of quality sleep at a consistent time each night. Lack of sleep can lead to increased appetite and decreased metabolism. Create a conducive sleep environment by keeping the bedroom dark and quiet and avoiding caffeine before bed.
• Stress Management: Stress can contribute to overeating and impaired metabolism. Find healthy ways to manage stress that work for you, such as pursuing hobbies, talking with friends, engaging in light exercise, relaxing with a bath or aromatherapy. Consulting a professional (e.g., counselor) can also be helpful if needed.
• Quitting Smoking and Moderating Alcohol: Smoking has adverse effects on overall health and indirectly contributes to weight gain susceptibility. Quitting smoking may initially lead to weight gain, but the health benefits are far greater. Alcohol is high in calories and stimulates appetite, so moderation is advisable.

Consulting a Medical Institution

If your self-guided lifestyle changes are not successful, or if you are at high health risk, do not hesitate to consult a medical institution.

• Consulting a Specialist: Doctors specializing in obesity (e.g., internal medicine physicians, diabetologists, endocrinologists) can medically evaluate the causes of overweight and develop an optimal treatment plan tailored to your individual condition.
• Nutritional Guidance from a Registered Dietitian: You can receive specific advice on meal content and support in creating meal plans. Learn practical tips for eating in a way that is sustainable.
• Exercise Guidance from an Exercise Therapist: Receive guidance on safe and effective exercise methods and programs.
• Medication Therapy: If diet and exercise alone are not sufficiently effective, or if your BMI is high or you have complications, a doctor may prescribe obesity treatment medications. These can help suppress appetite or reduce fat absorption. They must be used under a doctor’s prescription and guidance. Examples of such medications include GLP-1 receptor agonists (injectable or oral) and pancreatic lipase inhibitors (fat absorption inhibitors).
• Surgical Therapy: This is considered for severe obesity (BMI 35 or higher with complications, or BMI 40 or higher) when other treatment methods have not been effective. Surgical procedures include making the stomach smaller (e.g., sleeve gastrectomy) or altering the digestive and absorption pathways (e.g., gastric bypass surgery). Surgery requires specialized knowledge and skill, and its appropriateness is carefully assessed.

Addressing overweight is not about finding a magic bullet. Consistent small efforts each day lead to tangible results. Adopt a long-term perspective and, when needed, seek professional help to build a healthy lifestyle.

Frequently Asked Questions

Is Overweight a Disease?

While overweight is a broad concept, medically, "obesity" is defined as a disease, especially when accompanied by health problems or when the BMI is very high. Specifically, a state where BMI is 25 or higher and there is at least one obesity-related health disorder (e.g., Type 2 diabetes, hypertension, dyslipidemia, hyperuricemia/gout, coronary artery disease, stroke, sleep apnea syndrome/obesity hypoventilation syndrome, non-alcoholic fatty liver disease, menstrual irregularities/infertility, orthopedic disorders, obesity-related kidney disease), or severe obesity with a BMI of 35 or higher (regardless of complications), is diagnosed as "obesity." A BMI between 25 and 35 without complications is called "pre-obese" and is recognized as a precursor to obesity, indicating a high risk of future health problems, and healthy weight management is recommended. Thus, being in an overweight state itself is a significant risk factor that makes it easier to develop many lifestyle-related diseases and other conditions.

What are the Criteria for Overweight in Children?

Children are in the process of growth and development, so adult BMI criteria cannot be applied directly. For diagnosing overweight (obesity) in children, the "obesity index" is primarily used. This index is calculated as: (Actual Weight – Standard Weight) ÷ Standard Weight × 100 (%). Standard weight is determined based on statistical averages for sex and height. According to the Japanese Pediatric Society, an obesity index of +20% or more is classified as "obesity." Furthermore, an index of +30% or more may be classified as "moderate obesity," and +50% or more as "severe obesity." For infants (under 3 years), other indices like the Kaup index or Rohrer index may be used. Childhood obesity is likely to lead to adult obesity and early onset of lifestyle-related diseases (e.g., pediatric metabolic syndrome) and is a strong predictor of lifestyle-related diseases in adolescence and beyond. Therefore, appropriate guidance and management are crucial. Since there are significant individual differences in children’s growth, it is important not to self-diagnose but to consult a pediatrician, school doctor, local public health nurse, or other specialists for appropriate advice.

Is it Safe to Lose Weight Rapidly?

Losing weight rapidly over a short period (e.g., 1-2 kg or more per week) carries a high risk of harming health and is not recommended. Extreme calorie restriction or excessive exercise can lead to various problems such as:

• Rebound: Rapid weight loss can cause the body to perceive a state of starvation, leading to a strong activation of homeostatic functions that try to conserve energy. This can result in a body that easily regains weight, even more than before, when returning to a slightly less restrictive diet. It also increases the risk of overeating due to psychological backlash.
• Muscle Mass Loss: Not only body fat but also important muscle mass can be lost. Decreased muscle mass lowers basal metabolism (energy expended at rest), making it even harder to lose weight and easier to rebound.
• Nutrient Deficiencies: Severe lack of essential vitamins, minerals, and protein can lead to various health problems, including fatigue, dizziness, skin problems, hair loss, weakened immune system, and anemia.
• Gallstones: Particularly in women, rapid weight loss is known to disrupt the balance of bile components, making cholesterol gallstones more likely to form.
• Arrhythmia: Imbalances in electrolytes (especially potassium, etc.) can put a strain on the heart and potentially cause cardiovascular problems like arrhythmias.
• Mental Burden: Excessive dietary restriction can cause severe stress, making it difficult to continue dieting, leading to feelings of failure, decreased self-esteem, and even eating disorders (especially binge eating or anorexia nervosa).

A healthy and safe pace for weight loss is typically considered to be within 5% of your current weight per month, or about 0.5-1 kg per week, depending on your target weight. For example, for a person weighing 70 kg, a target weight loss of up to 3.5 kg per month would be appropriate. This corresponds to reducing daily calorie intake by about 300-500 kcal. The key is not rapid weight loss but establishing healthy lifestyle habits that can be sustained long-term. Consult a doctor or registered dietitian to create a plan that is realistic and sustainable for you.

How should overweight be considered for older adults?

For older adults, the assessment of overweight requires greater caution. In later life, muscle mass tends to decrease, while body fat percentage increases, leading to "sarcopenic obesity." Even with a normal BMI, having a high body fat percentage or, conversely, having a high BMI but low muscle mass, can increase the risk of falls, physical function decline, and lifestyle-related diseases. On the other hand, in older age, a certain amount of subcutaneous fat can be beneficial as an energy source during illness and as cushioning in case of falls. Therefore, for older adults, the focus should not solely be on weight loss but rather on maintaining and increasing muscle mass while aiming for an appropriate body fat percentage, and on maintaining or improving activity levels. Personalized advice from specialists (doctors, registered dietitians, physical therapists, etc.) tailored to the individual’s health condition and physical ability is essential.

Are Diet Supplements Effective?

Many diet supplements available on the market have not undergone the rigorous verification of efficacy and safety required for pharmaceuticals. While some ingredients may have scientific backing, their effects are limited, and in most cases, they serve only as supplementary aids to dietary and exercise therapy. Furthermore, some malicious products may contain impurities that can cause health problems or include illegal ingredients to boast efficacy. Instead of relying on supplements easily, first diligently work on basic measures like a balanced diet and appropriate exercise. If you are considering using supplements, be sure to consult a doctor or pharmacist and choose reliable products. It is important to understand that they are completely different from obesity treatment medications prescribed by a medical institution.

Why do I hit a "plateau" during dieting, and how can I overcome it?

When you are dieting, after losing a certain amount of weight, you may reach a point where your weight stops decreasing despite continuing your diet and exercise routine. This is known as a "plateau." Plateaus occur due to the body’s natural physiological response (homeostatic function) to reduce energy expenditure. When you lose weight, your body may interpret this as a state of starvation and attempts to conserve energy and maintain weight for survival. Additionally, the basal metabolic rate naturally decreases as body weight decreases.
A plateau can be seen as a period of adjustment for the body to get used to the new weight. Many people experience it, and it does not mean your diet has failed. You can overcome a plateau with appropriate strategies.
Key strategies to overcome a plateau include:

• Continue Your Current Method: Avoid panicking and resorting to extreme dietary restriction or excessive exercise. Instead, patiently continue with your healthy eating and exercise routine. Weight loss often resumes once your body adjusts to the new state.
• Re-evaluate Calorie Intake and Expenditure: You might be unknowingly consuming more calories or exercising less than you think. Review your food diary or use an activity tracker to check the balance between calorie intake and expenditure. As you’ve lost weight, your body requires less energy, so you might need to slightly lower your calorie target.
• Vary Your Exercise Routine: Doing the same exercises repeatedly can make your body too efficient at them, reducing their effectiveness. Try changing the type of exercise, slightly increasing the intensity, or incorporating strength training to provide new stimulation to your body. Strength training can help increase basal metabolism.
• Implement Strategic "Cheat Days": Some people find that having a planned day once a week where they slightly relax their dietary restrictions can help reset the body’s starvation response and stimulate metabolism. However, be mindful not to turn this into unplanned overeating.
• Prioritize Sleep and Stress Management: Getting enough sleep and managing stress are also important for maintaining normal metabolism.
• Consult a Professional: If a plateau lasts for a long time, consider consulting a registered dietitian, exercise therapist, or doctor. They can provide objective advice and support.

Plateaus are a common and natural part of the weight loss journey. It’s important to approach them patiently, persistently, and calmly.

How can I prevent regaining weight after losing it (rebound)?

Weight regain (rebound) is a challenge many people face after dieting. To prevent rebound and maintain a healthy weight long-term, your lifestyle habits after the diet period are crucial.
Key points to prevent rebound are:

• Avoid Extreme Diets: As mentioned earlier, rapid weight loss over a short period can make your body prone to regaining weight. It’s important to lose weight at a sustainable pace (around 5% of current weight per month) and, in the process, build healthy, sustainable eating and exercise habits.
• Continue the Healthy Eating Habits You’ve Learned: It is most important to continue the balanced diet, appropriate calorie intake, and healthy eating patterns you adopted during the diet period, even after reaching your target weight. If you revert to unhealthy eating habits, you will likely regain the weight.
• Maintain Your Exercise Routine: Exercise not only increases energy expenditure but also helps maintain and increase muscle mass, boosting metabolism and making it harder to rebound. Continue exercising regularly even after losing weight. It doesn’t need to be high intensity; finding enjoyable activities like walking or light strength training is key to consistency.
• Check Your Weight Regularly: Make it a habit to weigh yourself regularly, perhaps once a week. Noticing slight weight increases early allows for prompt adjustments to prevent a full rebound.
• Pay Attention to Overall Lifestyle: Lack of sleep, stress, and excessive alcohol consumption can also increase the risk of rebound. Aim for a healthy and regular lifestyle.
• Set a New Goal of "Maintaining" Your Weight: By consciously setting a new goal of "maintaining" the weight you’ve lost, rather than just "losing weight," you can help sustain motivation.
• Recognize Small Changes and Address Them Early: If you notice a slight weight gain, reduced exercise, or slipping eating habits, try to get back on track immediately. It’s easier to address problems when they are small.
• Have a Support System: Sharing your goals or exchanging information with family, friends, or fellow dieters can help you stay consistent. Continuing to receive support from medical institutions or professionals can also be effective if needed.

Rebound is not uncommon. If you do regain weight, don’t blame yourself excessively. Instead, analyze the reasons and restart healthy lifestyle habits.

What are some examples of healthy snacks?

Snacking is meant to curb hunger between meals or supplement necessary nutrients in small amounts. Unhealthy snacks (such as chips, chocolates, and sugary drinks) can lead to excess calorie intake and rapid blood sugar spikes, contributing to overweight.
Key points for choosing healthy snacks are:

• Low Calorie, Low Sugar: It’s important not to add unnecessary calories.
• Nutritious: Choose snacks that contain beneficial nutrients like vitamins, minerals, dietary fiber, and protein.
• Small Portions: A snack is not a meal. Avoid overeating.
• Satisfying: Snacks with some chewiness or those containing dietary fiber or protein can help you feel satisfied and potentially prevent overeating at the next meal.

Examples of specific healthy snacks include:

• Fruits: Rich in vitamins, minerals, dietary fiber, and water. However, fruits also contain sugar, so moderation is important. Apples, strawberries, and blueberries are good options.
• Nuts: Contain healthy fats, dietary fiber, minerals, and protein. A small handful can be satisfying, but they are calorie-dense, so be careful not to eat too much. Almonds, walnuts, and cashews (unsalted, roasted) are good choices.
• Plain Yogurt or Skyr: Rich in protein and calcium. Choose unsweetened varieties.
• Boiled Eggs: An easy source of good quality protein.
• Vegetable Sticks: Cucumber, carrots, celery, etc. They are very low in calories and high in fiber. A small amount of oil-free dressing or dip is acceptable.
• Dried Sweet Potatoes or Baked Sweet Potatoes: High in dietary fiber and filling, but also contain carbohydrates, so watch your portion size.
• Low-Carbohydrate Protein Bars: Provide a convenient source of protein. Check the nutrition label and choose options that are low in sugar and fat.

The best time for a snack is typically between lunch and dinner, when you feel particularly hungry. Instead of snacking habitually out of boredom or inertia, make a conscious choice from healthy options in small amounts when you genuinely feel hungry.

Conclusion

Overweight is not merely excess body weight; it is a condition characterized by excessive accumulation of body fat and is a medically significant issue that increases the risk of many serious diseases, including diabetes, high blood pressure, dyslipidemia, cardiovascular diseases, and sleep apnea syndrome. Checking your BMI and, if necessary, getting a comprehensive evaluation from a medical institution, including waist circumference, body composition, and blood tests, is very effective for accurately understanding your health status.

The main cause of overweight is an imbalance between energy intake and expenditure, closely related to lifestyle habits such as a high-calorie, high-fat diet, lack of exercise, insufficient sleep, and stress. Genetics, medications, and specific diseases can also play a role, but in most cases, improving lifestyle habits is the most effective measure.

Resolving and preventing overweight requires sustainable lifestyle changes, including adjusting your diet (calorie control, balance, eating patterns) within a reasonable range, regular exercise (combining aerobic and strength training), sufficient sleep, and stress management. These measures may not yield results overnight, but with consistency, they will lead to a healthier body and reduce the risk of future diseases.

If you find it difficult to make changes on your own, or if you have a high BMI, complications, or suspect an underlying disease as the cause, do not hesitate to consult a medical institution and seek support from specialists such as doctors, registered dietitians, or exercise therapists. Scientifically based personalized advice, and if necessary, medication therapy or surgical treatment, are also options.

Improving overweight and maintaining a healthy weight is not just about changes in appearance; it significantly enhances Quality of Life through improved physical health, increased activity levels, and restored confidence. Above all, it is a crucial investment in extending your healthy lifespan and living your life to the fullest in the future. We hope this article serves as a stepping stone towards achieving your healthy lifestyle.

[Disclaimer]
This article is intended to provide general information about overweight. For individual health conditions and treatment, please always seek diagnosis and guidance from a doctor or specialist. We assume no responsibility for any outcomes resulting from actions taken or not taken based on the information provided in this article.