Why do I gain weight after 40 even though I eat less?

Many people entering their 40s often experience the same phenomenon: They eat less but their weight still increases little by little. There are many factors that affect this phenomenon.

After the age of 40, many people still gain weight even though they feel they eat less than before due to the following reasons:

Hormone reduction

After the age of 40, both men and women experience significant hormonal changes. This is considered a factor that increases fat accumulation, according to the health website Healthline (USA).

Reduced physical activity is one of the reasons why people over 40 are prone to gaining weight even though they eat less.

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In women, estrogen levels drop before and after menopause, changing the way the body distributes fat. Fat tends to move from the hips and thighs to the abdomen. Meanwhile, in men, testosterone levels gradually decline at a rate of about 1% per year after age 30, reducing muscle mass and slowing fat burning. The hormones leptin and ghrelin, which regulate hunger and satiety, also become imbalanced with age and lack of sleep.

Loss of lean muscle mass

From age 40 onwards, the human body begins to lose an average of 3–8% of lean muscle mass per decade. Because muscle consumes more energy than fat, as muscle mass decreases, total daily energy expenditure also decreases.

Even if you maintain your old diet, this amount of calories becomes surplus to your body's new needs. At the same time, when muscle mass decreases, insulin sensitivity also decreases, making it difficult for blood glucose to be absorbed into the muscles and instead accumulates as fat.

There is a growing body of scientific evidence that strength training in middle-aged adults 2–3 times per week for 8–12 weeks can help increase lean muscle mass and decrease total body fat, even without dietary changes. Resistance training significantly improves muscle mass, reduces body fat percentage and visceral fat, and contributes to improved metabolism and insulin sensitivity.

Stress and sleep disorders

After age 40, stress from work, family responsibilities and lack of sleep become more common, leading to long-term high levels of the hormone cortisol. This condition leads to increased fat accumulation in the abdomen.

The reason is that cortisol stimulates triglyceride synthesis in abdominal fat cells and inhibits fat breakdown. The result is increased visceral fat and impaired metabolism, thereby increasing the risk of metabolic disorders and cardiovascular diseases.

Reduced physical activity

As we enter middle age, many people become less active due to being busy or not being as flexible as before. When activity decreases, the amount of calories burned through daily activities drops dramatically. Just sitting 2-3 hours more per day compared to the previous decade can reduce energy consumption by 200-300 calories/day.

In addition, circadian rhythm disorders caused by staying up late or working under stress also disrupt insulin and melatonin hormones, leading to abdominal fat accumulation and reduced energy expenditure while resting, according to Healthline .

Source: https://thanhnien.vn/vi-sao-an-it-nhung-van-tang-can-sau-tuoi-40-185251030152932735.htm