Why does the yo-yo effect happen again after a difficult diet?

The most representative cause of the yo-yo phenomenon is a decrease in basal metabolic rate. When weight is lost suddenly, fat decreases, but at the same time, muscle mass also diminishes. The amount of calories roughly consumed by 1kg of skeletal muscle per day is about 13 kcal, so the more 'muscle loss' during dieting, the more the basal metabolic rate inevitably drops sharply.
 
Reducing the amount of food consumed itself is a factor that lowers basal metabolic rate. If you drastically cut down on your food intake, your body slows down metabolism to sustain life, which decreases basal metabolic rate and causes you to become more prone to gaining weight.
 
When the basal metabolic rate decreases and food intake is also reduced, instead of using body fat as an energy source, proteins in the muscles are broken down and converted into glucose, leading to a decrease in muscle mass and creating a vicious cycle. However, if a person who has already exhausted energy returns to their previous diet, weight gain will become even easier, and it is unlikely that their basal metabolic rate will recover.

 
When weight loss occurs rapidly, changes also happen in hormones related to appetite. The secretion of 'ghrelin,' a hormone produced in the gastrointestinal tract that stimulates appetite, increases, while 'leptin,' a hormone secreted by adipose tissue that suppresses appetite, decreases. In other words, if someone excessively restricts their diet in a short period to lose weight, there is a higher risk of overeating and binge eating after the diet.

Extreme dieting causes hunger, which reduces the body's energy sources and increases cortisol, a stress hormone. Shin Seung-ryeol, a sports expert at HiDoc, explained, "When exposed to stress, some people experience increased appetite while others suppress it," adding, "Whether eating more or less, it disrupts regular eating habits and hampers the effectiveness of dieting."
 
A research team from Ohio University in Ohio, USA, announced that stress reduces calorie expenditure ability. Experimental subjects who experienced stress had lower fat consumption and higher insulin levels, which contribute to fat accumulation. The average calorie expenditure of the experimental group was 104 kcal lower than that of the control group.
 
In this way, stress can cause you to give up on dieting and may even lead to weight gain. However, even after reaching the target weight, stress experienced during dieting can trigger the yo-yo effect. This is because the psychological desire to reward oneself for the difficult experience of losing weight may be activated.

When dieting and yo-yoing happen repeatedly, it is easy to feel frustrated. Seeing the hard-earned weight come back or not reaching the target weight can lead to feelings of depression. These negative emotions, if repeated, may increase the risk of developing depression, so caution is necessary.
 
Various physical symptoms may also accompany it. Repeated weight gain and loss can cause muscle loss, remove calcium and minerals from bones, and worsen bone health, as well as increase the risk of heart disease. According to the American Heart Association (AHA), women who have attempted weight loss after menopause and experienced repeated yo-yo dieting are 3.5 times more likely to die from a heart attack and 1.7 times more likely to die from coronary artery diseases such as angina than those who do not.
 
To minimize these issues, it is important to set achievable long-term goals rather than forcing rapid weight loss in a short period. Experts advise that losing about 10% of body weight over six months is appropriate.
 
Additionally, to prevent yo-yo dieting, it is recommended to eat slowly and thoroughly chew during meals. This allows you to feel full quickly, leading to the consumption of smaller amounts of food, and also speeds up the digestion process in the body. Reducing the intake of carbohydrates and increasing protein consumption also helps promote muscle growth, which aids in weight loss.
 
It is also important to manage stress well during the dieting period. If you have foods you want to eat, don't just suppress the urge; instead, consume them about 1 to 2 times a week, but limit the intake to small portions, and then pay more attention to your diet for the next one or two days.

It's a story I know very well, but not an easy one.

Let's set long-term goals rather than short-term weight loss!!

You who are diligently dieting today as well!

Fighting!!

Source = Choi Jae-a, HiDoc Intern Reporter