Gastroenterologist explains why those who undergo drastic weightloss often regain the kilos; who is at greater risk

The body stops creating new fat cells after teenage years, making weight management harder for those who were overweight as teens.

How inspiring does it feel when we see a friend or even a celebrity shed the extra pounds to reveal a fit and toned self. They work out at the gym, keep their diet in check and impress one and all with their dedication. However, the lost kilos do not always stay off. Many often pack on those pounds again, often in no time at all. Why does that happen and why do some people find it so hard to stay lean and fit?

Why can't we keep the shed weight off?

Gastroenterologist Dr Palaniappan Manickam shared a video recently on Instagram on this topic. The California-based doctor explained why individuals often regain weight after dieting, attributing this phenomenon to fat cells that shrink but do not vanish, similar to deflating balloons.

“Have you ever wondered why you gain back all the weight after a diet? It is not your fault. It is your fat cells. When you go on a diet and eat fewer calories, your fat cells shrink. But they do not disappear. They just deflate like a balloon. And the second you start eating more again, they inflate right back. That's why that weight that you lost comes back so fast,” he said in the video.

He added that the number of fat cells is typically set after the teenage years, suggesting that individuals who were overweight during their youth may have a higher baseline number.

Teenage years set the course

“And what most people don't know is your body stops making new fat cells after your teenage years. So if you are overweight during your teens, you probably have more fat cells than others. That's why people who are overweight early in life may find it harder to manage their weight in adulthood. So when you lose fat too fast, those fat cells start screaming for food and that is why crash diets feel impossible to stick to,” he added.

“This is why sustainable weight loss matters. The goal is not just to lose fat. It is to build healthy habits that improve your energy, digestion, and sleep where weight loss becomes a natural side effect of your process.”

Wondering how to achieve sustainable weight loss? It includes making staying active and eating right a part of your daily life and not just a momentary exercise to be followed for a few months.

Follow this five-step guide by fitness coach Rajni Singh to achieve sustainable weight loss. She shows how to “cut through the noise if you’re serious about changing your body—your energy, your strength, your confidence—it comes down to the basics. Not trends, not shortcuts. Just real, sustainable habits.”

Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.