Scientific weight loss: combining small, restricted food intake with aerobic exercise and behavioral changes

Extensive research findings, based on varying degrees of calorie restriction (e.g., 400kcal, 500kcal, 800kcal, 1200kcal per day) combined with or without exercise, indicate that a slight reduction in dietary calorie intake—i.e., a daily calorie deficit of 500–1000kcal (for obese children aged 1–3 years, a daily calorie deficit of 200–500kcal, not exceeding 500kcal)—combined with appropriate aerobic exercise, is a generally recognized, relatively reasonable, safe, and effective method for weight loss. This method maximizes the prevention of dehydration, preserves lean tissue, and consumes body fat.

A slightly restricted calorie diet should meet the following conditions:

(1) Daily calorie intake should not be less than the safe energy level of 1200kcal per day.

(2) A weight-loss diet should be a balanced diet, with protein accounting for 12%–18% of total calories and fat accounting for 20%–30%. It should minimize saturated fatty acids and maximize the use of unrefined complex sugars.

(3) It should contain essential nutrients and have a high nutrient density.

(4) It should be rich in fiber to accelerate the passage of food through the digestive tract, reduce calorie absorption, and provide a feeling of fullness.

(5) It should align with the dietary habits, taste preferences, economic conditions, ease of preparation, and the need for personal enjoyment and variety required by those trying to lose weight.

The key to a weight-loss diet is a negative energy balance, which is not significantly related to the composition of the food. Using high-protein or high-fat diets for weight loss lacks experimental evidence and is controversial. High-protein diets have a high SDA (saturated dietary energy) effect. Protein foods have a low digestibility coefficient, and the digestion process (including liver absorption of amino acids) consumes energy. However, excessive protein intake can suppress appetite (possibly due to over-reliance on fat metabolism), increase the burden on the liver and kidneys, and cause dehydration and electrolyte imbalances. High-fat and low-sugar diets can cause a series of side effects, including ketosis, dehydration, loss of urinary sodium and other electrolytes, increased kidney burden, lean tissue loss, hypokalemia, arrhythmia, glycogen depletion, increased blood lipids, and fatigue. Therefore, many reports still emphasize that weight-loss diets should be balanced. To achieve a balanced and diverse diet, food exchange programs can be used to create recipes containing different energy levels and input them into a computer to accommodate individual differences among individuals trying to lose weight.

Reasonable weight loss should not employ starvation or semi-starvation diets. Starvation or semi-starvation diets may only be tried in severely obese individuals (body fat percentage greater than 40%–50%). Such diets can sometimes change or break established unhealthy eating habits, laying the foundation for long-term weight control. However, the use of starvation diets to treat obesity or lose weight should be under medical supervision or hospitalized. Using appropriate exercise and dietary control to lose weight is only the first step in maintaining a suitable or healthy weight. To maintain a suitable weight and body fat percentage or consolidate the weight loss results, it is necessary to seriously implement new lifestyle or behavioral changes, including changes in dietary habits and regular exercise. For example, avoiding or reducing high-fat and high-sugar foods, avoiding snacks, avoiding sitting and watching TV after meals, and establishing a regular exercise habit that is maintained throughout life. In summary, reasonable weight loss measures should be:

Slight restriction of dietary calories + appropriate aerobic exercise + behavioral changes