People who are trying to eat healthy, either to lose or gain weight, or stay fit, often face unique challenges depending on their goal.

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Someone who is on the heavier side and wants to lose weight may find themselves unable to lose weight easily despite eating less. At the same time, a person on the slimmer end of the scale who is trying to bulk up often discovers that no matter how much he eats, rarely anything is added to his frame.
On February 20, Dr. Saurabh Sethi, a California-based gastroenterologist trained at AIIMS, Harvard and Stanford universities, explained the scientific reason behind this phenomenon on his Instagram account on February 20.
How does BMR affect body weight?
According to Dr. Sethi, weight loss or gain due to diet is affected by an individual’s basal metabolic rate, or BMR. He defined it as the energy that the body uses simply to survive and perform basic metabolic functions such as breathing, thinking, digesting food, and pumping blood.
“Everyone’s drive is different,” Dr. Sethi said. Some people are born with a faster BMR, which can be a result of genetics, thyroid function, hormones, or increased muscle mass. They burn more calories. Others with a slower basal metabolic rate burn fewer calories at rest.
When it comes to burning calories, muscle plays a major role. Muscle tissue burns three to five times more calories than fat while the body is at rest. Therefore, more muscle leads to higher burning around the clock. Muscles can be developed through regular exercise. People with more muscle can eat more without gaining weight.
“People with less muscle burn fewer calories at baseline,” Dr. Sethi noted. “This occurs after crash dieting, long-term calorie restriction, or muscle loss with age.”
Aside from muscle, hormonal imbalances like insulin resistance make it easier to store fat and harder to burn it. This is common in individuals with fatty liver, polycystic ovary syndrome, prediabetes, and prediabetes.
Differences between the two groups
Dr. Sethi highlighted the common differences between people who gain weight despite eating less and those who eat more but remain thin.
People who are overweight and “eat little” often suffer from:
- Slowed metabolism
- Decreased muscle mass
- Hormonal imbalance
- High cortisol/hidden stress
- Bad sleep
- Metabolic adaptation after diet
Those who “eat anything” but remain thin usually have:
- High metabolic rate
- Better insulin sensitivity
- More daily movement
- More muscle mass
“A little daily movement adds up more than people think,” the gastroenterologist said. “The goal is not to eat less, but to improve how your body burns through more muscle, stable hormones, better sleep, and consistent movement.”
Note to readers: This article is for informational purposes only and is not a substitute for professional medical advice. Always seek the advice of your physician with any questions about a medical condition.
This report is based on user-generated content from social media. HT.com has not independently verified these claims and does not endorse them.
