The real reason your weight fluctuates: What a new study reveals

Here’s the thing with weight – it isn't an easy feat to get it under your control. If you are someone who struggles with shedding weight, you probably are the very person who goes through a hard time keeping it in line as well. What does that mean? You may have been able to lose some weight thanks to the rigorous workout routines and a strict diet. But, if loosen your grip on the rein a little, and bam! The scale is on the reverse gear again!

Now, getting on the scale is always a bit nerve-wracking. Some fluctuation is natural, but if you're constantly seeing that number go up and down, which is popularly known as the ‘yo-yo effect’, it can take a toll on your motivation, as well as self-esteem.

According to a new study, there might be more to the ‘yo-yo effect’. As per the findings published recently in ‘Nature’, the body may ‘remember’ being overweight, keeping some stuck in this cycle!

What is the ‘yo-yo effect’?

The yo-yo effect is a very common situation in which people struggle to maintain their target weight during their weight loss programs. In the beginning, people start losing weight, but then after their weightless regain all the weight they have lost.

Researchers from ETH Zurich studied the yo-yo effect in mice, analysing fat cells from overweight mice and those that shed weight by dieting. They observed that the obese mice also experienced changes in their fat cells—and after they lost weight, these modifications stayed in place. When they ate a ‘high-fat diet’ again, they regained weight more quickly than those whose cells didn't have these memories.

Ferdinand von Meyenn, professor of nutrition and metabolic epigenetics at ETH Zurich, explained in a press release outlining the findings, saying, “The fat cells remember the overweight state and can return to this state more easily.” He added that fat cells' ‘memory’ of their obese state then prepares them ‘to respond quicker, and maybe also in unhealthy ways, to sugars of fatty acids’.

Researchers even found evidence of the ‘molecular basis for the yo-yo effect’ in humans as well. They analysed fat tissue biopsies from overweight people who had stomach reduction or gastric bypass surgery and compared them with fat from people at a healthy weight who had never been obese. As it turned out, stated by ‘The Guardian’, fat cells that had experienced obesity responded to food differently during testing, growing faster by taking in nutrients faster.

Von Meyenn mentioned to ‘The Guardian’ that, apart from the fat cells having ‘the memory’, other parts of the body could contribute to the yo-yo effect too. He added that, future research is needed to examine whether cells in the brain, blood vessels, or other organs could play a role.

Although researchers may have had a breakthrough in understanding why people's weight won't stop fluctuating, there isn't as much clarity on how long fat cells remember obesity. However, they do know that fat cells don't have as quick of a turnover. Study author Laura Hinte, a doctoral student at ETH Zurich, explained in the press release, “Fat cells are long-lived cells. On average, they live for ten years before our body replaces them with new cells.”

Causes of the yo-yo effect: The reasons for the yo-yo effect are varied but mainly include:


Unhealthy weight reduction methods: Inappropriate weight loss methods eventually result in increased chances of having the yo-yo dieting such as lack of proper exercise and using weight loss pills. Particularly in healthy young people, the yo-yo effect might not be usually seen during the first weight control program. However, if these unhealthy weight loss habits have been continued, it is increasingly challenging to lose weight, very often to finally end with the yo-yo effect.

Calorie restriction and fasting diets: Although the restriction of calorie intakes quickly contributes to weight loss due to the reduction in muscle mass instead of the body fat. When muscle mass decreases, the body automatically adapts by slowing down metabolism. In fact, researchers suggest that this lower metabolism may partly explain why people regain weight once they go off their calorie-restricted diets. It eventually becomes more difficult to continue losing weight due to reduced metabolic function.

How to manage the yo-yo effect?

Researchers noted that altering or erasing this memory of obesity isn't doable right now. As per Hinte, “Maybe that’s something we’ll be able to do in the future, but for the time being, we have to live with this memory effect.” According to von Meyenn, this reinforces the need to maintain a healthy weight. He said, “It’s precisely because of this memory effect that it’s so important to avoid being overweight in the first place. Because that’s the simplest way to combat the yo-yo phenomenon.”

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