bubble_chart Overview

Obesity is a nutritional disorder caused by excessive nutrient intake, characterized by an excessive accumulation of body fat leading to overweight. If a child is overweight but does not have excessive fat content, it cannot be diagnosed as obesity. Approximately one-third of children with obesity will develop adult obesity, which poses risks for various diseases such as diabetes, atherosclerosis, hypertension, coronary heart disease, poor respiratory ventilation, and osteoarthritis. Additionally, obese children may exhibit reduced stress responses, weakened resistance to infections, and intolerance to anesthesia and surgical procedures. Treating obesity is highly challenging, and prevention requires long-term adherence to measures, making it one of the more difficult clinical issues in pediatrics.

bubble_chart Clinical Manifestations

Children with obesity generally grow slightly faster in height than non-obese children. Their bone age is normal or exceeds their actual age. Sexual maturation is normal or advanced. Boys may appear to have smaller external genitalia due to the concealment by pubic fat, but they are actually normal. Obese infants and young children are prone to respiratory infections. Older obese children are susceptible to slipped capital femoral epiphysis and Blount's disease, with the severity of tibial deformity in the latter being related to the degree of obesity. The incidence of hypertension in obese children is approximately seven times higher than in non-obese children, and the prognosis is poor. Severely obese children may also experience episodes of sleep apnea, daytime drowsiness, poor alveolar ventilation leading to hypoxemia, polycythemia, cyanosis, cardiomegaly, and even congestive heart failure.

bubble_chart Auxiliary Examination

1. The basal plasma insulin level is higher than normal (up to 2-3 times the normal value), but due to the presence of insulin resistance factors, glucose tolerance is often impaired, and blood sugar tends to increase. Total blood lipids, cholesterol, triglycerides, and free fatty acids are often elevated.
2. When poor ventilation exists, the partial pressure of carbon dioxide in the blood increases, the partial pressure of oxygen decreases, and the blood carbon dioxide combining power rises, resulting in respiratory acidosis, followed by polycythemia.
3. Ultrasound examination may reveal varying degrees of fatty liver.

bubble_chart Diagnosis

(1) Diagnostic Criteria Clinically, the standard weight for children of the same gender and height is commonly used as the reference. If the weight exceeds the standard weight by 20%, it can be diagnosed as obesity. An excess of 20–30% is classified as grade I obesity, 30–50% as grade II, and >50% as grade III. An excess of 10–20% is considered overweight. There are two possible explanations for weight exceeding the standard: one is an increase in body fat content, and the other is an increase in lean tissue such as muscle or a larger skeletal frame. Using weight alone as a diagnostic criterion for obesity cannot distinguish between these two scenarios, thus having certain limitations. Skinfold thickness is a specific indicator of body fat content. Diagnosing obesity based on skinfold thickness can compensate for the limitations of the weight criterion. Obesity can be diagnosed if the skinfold thickness exceeds the 85th percentile, but currently, there is no population reference data for skinfold thickness available in China.

(2) Medical History

There is a history of excessive food intake. Overfeeding during artificial feeding and the premature introduction of starchy foods (within 1–2 months after birth) are contributing factors to infant obesity. High consumption of staple foods and/or meat, low physical activity, and a preference for sweets and/or fatty foods are contributing factors to childhood obesity. Once obesity develops in older children, the energy level required to maintain obesity may be equal to or slightly lower than that of non-obese children.

bubble_chart Treatment Measures

(1) Dietary Management The total dietary energy should be reduced while maintaining normal growth and development, ensuring balanced nutrition, and achieving steady weight loss. Weight reduction should be synchronized with improving dietary structure and habits. The steps for dietary management are as follows:

1. First, understand the child's previous dietary energy intake level and dietary structure. This can be obtained through dietary recall surveys and calculations.
2. Gradually reduce the original total energy intake until the expected weight loss is achieved. Generally, for grade I obesity, a daily negative energy balance of 125–250 kcal is appropriate; for moderate and grade III obesity, a reduction of 250–500 kcal or more per step is recommended. For grade I obesity, a monthly weight loss of 0.5–1.0 kg is suitable, while for moderate and grade III obesity, a weekly weight loss of 0.5–1.0 kg is ideal.
3. Dietary protein should be ensured at the normal supply level or slightly higher. The proportion of energy from protein increases as total energy decreases, but should not exceed 20–30%, as excessive amounts may lead to liver and kidney injury.
4. Dietary fat intake should be appropriately limited, preferably not exceeding the normal fat energy ratio (25–30% for children). Excessive fat can cause ketosis, while too little may reduce satiety. Cholesterol intake should ideally be ≤300 mg per day.
5. Carbohydrates remain the main energy source, accounting for about 40–55% of total energy. Excessive restriction of carbohydrates may lead to negative nitrogen balance and ketosis. However, low-molecular-weight sugars (such as monosaccharides and disaccharides) should be limited as they are unfavorable for weight loss, while dietary fiber should not be restricted.
6. Low-calorie, high-volume vegetables such as wildcelery herb, bamboo shoots, and radishes can be prioritized. Starchy vegetables like potatoes and sweet potatoes should be limited or counted as part of carbohydrate intake.
7. Fruits high in sugar should be moderately restricted, while those low in sugar, such as citrus, pears, and strawberries, can be consumed in moderation.
8. The number of daily meals should be three or small, frequent meals.
9. Once weight drops to 110% of the standard weight, dietary restrictions can be discontinued. Maintain total energy at normal levels, with protein, fat, and carbohydrate energy ratios at 12–15%, 25–30%, and 55–65%, respectively. Avoid reverting to previous unhealthy dietary levels or patterns.

(2) Exercise and Physical Activity Combining dietary management with exercise accelerates weight loss. Physical activity should be regular, daily, and sustained over many years without interruption. Recommended exercises include swimming, walking, tai chi, and table tennis. Strenuous exercise is generally not well-tolerated by obese children and may sharply increase appetite, so it should be avoided. Exercise can also lower serum insulin and triglyceride levels.

(3) Medications Anorexigenic agents are effective for most children, such as diethylpropion, chlorphentermine, and fenfluramine, though the latter may affect growth. Amphetamines are strictly prohibited in children due to their addictive potential. If anorexigenic agents show no effect within 1–2 weeks, they should be discontinued.

(4) Group Therapy Approach Organizing obese children into a 2–3 week summer (or winter) camp with structured, disciplined regular exercise and a low-energy balanced diet can result in an average weight loss of 4–5 kg. However, care must be taken to prevent relapse after the structured environment ends.

(5) Treatment of Hypoxemia For severe obesity complicated by shortness of breath, hypoxemia, and heart failure, in addition to a low-calorie diet, cardiac agents, diuretics, and low-concentration oxygen therapy should be administered. Anticoagulant therapy may be used to prevent thrombosis.

(6) Surgery Surgery is the last resort for treatment. It is only considered for patients who are 200% overweight or those who are less than 200% overweight but suffer from significant obesity-related complications such as diabetes, hypertension, sleep apnea, or alveolar hypoventilation. Moreover, surgery is not an option unless all conservative treatments have failed. The 7-year mortality rate for patients meeting surgical criteria is approximately 25%, which exceeds the risks of the surgery itself. The most common procedure is gastric bypass surgery, with a mortality rate of less than 1% and surgical complications such as subhepatic abscess, wound dehiscence, or anastomotic fistula occurring in about 5–10% of cases.

bubble_chart Prevention

Preventing childhood obesity starts with the mother. Mothers should cultivate healthy dietary habits before pregnancy to reduce the likelihood of giving birth to obese children and ensure that infants are positively influenced by their mothers from birth. Additionally, encouraging breastfeeding, avoiding the premature introduction of starchy foods, and providing children with a balanced diet are essential. Regular monitoring of a child's growth and development, along with prompt correction of any issues, is also crucial.

bubble_chart Differentiation

The following diseases are all accompanied by obesity and need to be differentiated from simple obesity in children. However, these diseases account for less than 1% of obese children and are often accompanied by short stature, delayed bone age, and delayed development of secondary sexual characteristics:

1. Endocrine causes: Cushing's syndrome, hypothyroidism, hyperinsulinemia, growth hormone deficiency, hypothalamic dysfunction, Prader-Willi syndrome (hypogonadism), Stein-Leventhal syndrome (polycystic ovaries), pseudohypoparathyroidism type I.
2. Genetic syndromes: Turner syndrome, Laurence-Moon-Biedl syndrome, Alstrom-Hallgren syndrome.
3. Other syndromes: Cohen syndrome, Carpenter syndrome.