Weight gain is a complex process influenced by many factors beyond just calorie intake. These include energy consumption and expenditure, physical activity levels, sleep quality, stress, medications, age-related hormonal changes, and thyroid disorders. While reducing calorie intake can lead to initial weight loss, the body often adapts, making sustained loss challenging.

Initially, when you reduce calorie consumption, your body seeks other energy sources to maintain basic functions. One of the first sources utilized is glycogen, a stored form of carbohydrates. Glycogen is partly composed of water and is typically stored in muscles and the liver. As the body converts glycogen into energy, you may experience initial weight loss, but this is a temporary effect.

When calories are severely restricted over time, the body adapts to an "energy-saving mode," automatically slowing its basal metabolic rate to conserve life-sustaining functions. This reduction in daily calorie burn makes it easier to accumulate fat, even when consuming very little food.

A diverse daily meal with various nutrients supports weight management. Photo: Tam Anh General Hospital

Gaining weight despite eating less can also result from the quality of food consumed. Eating small portions but frequently choosing high-energy foods like sugary drinks, processed items, or fried dishes can create an energy surplus, leading to fat storage. Additionally, insufficient physical activity means total energy expenditure remains lower than intake, contributing to weight gain. After 30-40 years of age, muscle mass tends to decrease without regular exercise. Since muscles burn more energy than fat, a reduction in muscle mass also lowers the basal metabolic rate.

Chronic stress elevates the hormone cortisol, which can promote fat accumulation, particularly around the abdomen. Similarly, inadequate sleep disrupts hormones that regulate hunger and satiety, making the body more prone to storing energy.

To effectively manage weight, it is important to balance meals and avoid consuming less than 1,200 calories per day, as severe restriction can trigger intense hunger and cravings, leading to overeating later. Focus on a diverse and balanced intake of nutrients, limiting free sugars and saturated fats. Maintain at least 150-300 minutes of moderate physical activity each week, improve sleep quality, and manage stress levels.

If your weight does not improve despite these efforts, it is advisable to consult an endocrinology and metabolism specialist for a comprehensive assessment and appropriate treatment plan.

Dr. Tran Thuy Ngan, Specialist Level II

Head of Endocrinology - Diabetes Unit

Tam Anh General Clinic District 7