Behind every public figure's appearance lies a personal health regimen. This series examines the diets, exercise routines, procedures, and beauty and fashion choices of people in the spotlight.

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Big Mama member Lee Young-hyun has drawn attention to weight management after sharing an update on her appearance following a 33 kg weight loss.

On Oct. 24, Lee's agency, H.O. Entertainment, posted several photos taken at a performance venue on its official SNS account. Lee had previously appeared on a YouTube channel and said she had lost 33 kg by changing her eating habits — including drinking warm water regularly and cutting out snacks.

After successfully losing weight, keeping it off becomes the critical challenge. When body weight drops, the body changes how it burns energy and alters the hormones that regulate appetite. Experts emphasize that maintaining sustainable eating habits and physical activity in daily life — rather than severe dietary restriction — is essential for long-term weight management.

Why the body fights back: the science behind weight regain

Weight regain after dieting is closely tied to the body's physiological adaptations. As weight decreases, so does the energy the body needs to sustain itself. At the same time, hormonal shifts drive appetite upward, creating conditions in which weight can creep back even when eating less than before the loss.

According to the National Institute of Diabetes and Digestive and Kidney Diseases, metabolism slows during weight loss and daily calorie needs fall in line with the lower body weight. Hormonal changes that affect appetite further complicate the effort to keep weight off.

A study published in The New England Journal of Medicine confirmed that appetite-related hormonal changes persist for an extended period after weight loss.

Researchers monitored hormonal changes before and after weight loss in 50 overweight and obese adults. Participants lost an average of 13.5 kg. Levels of appetite-suppressing hormones such as leptin and peptide YY fell, while ghrelin — which stimulates hunger — rose. These changes remained largely in place a year after the weight loss, and participants reported higher levels of hunger than before they had lost the weight.

A separate study quantified the increase in appetite that follows weight loss. An analysis by US researchers published in the journal Obesity estimated that for every kilogram lost, the drive to consume energy through appetite increases by about 100 kilocalories per day. The researchers said this rise in appetite may have a greater impact on weight maintenance than the accompanying drop in energy expenditure.

After losing weight, therefore, the priority should be managing calorie intake steadily while staying satisfied — not slashing portion sizes drastically. Eating foods rich in protein and dietary fiber and avoiding skipping meals can help.

Drinking 500 ml of water before meals: what 12 weeks of data showed

The habit of drinking water that Lee mentioned is another lifestyle tool for weight management. Water contains no calories yet takes up space in the stomach, so drinking it before a meal can temporarily increase the sense of fullness and help moderate food intake.

In 2015, the journal Obesity published the results of a clinical trial by researchers at the University of Birmingham examining how drinking water before meals affects weight loss.

The researchers divided 84 obese adults into two groups and observed them for 12 weeks. One group drank 500 ml of water 30 minutes before each main meal; the other was asked to imagine feeling full before eating. The water-drinking group lost an average of 1.3 kg more than the comparison group.

A study by researchers at Virginia Tech that followed 48 overweight and obese middle-aged adults produced similar results. Participants who drank 500 ml of water before every meal alongside a calorie-restricted diet lost about 2 kg more over 12 weeks than those who only followed the diet.

However, the main benefit of drinking water lies in moderating food intake and replacing high-calorie beverages. There is insufficient evidence that warm water reduces body fat more than cold water. The additional energy the body expends regulating temperature after drinking warm water is also not large enough to meaningfully affect weight loss.

To make drinking water a regular habit, consider having a glass before each meal or replacing sugary drinks with water. Daily fluid needs vary by body size, activity level, temperature and health status, so drinking excessive amounts at once should be avoided. People who must limit fluid intake due to heart or kidney conditions should follow their doctor's guidance.

Why cutting snacks helps — and why exercise matters too

Reducing snack consumption, which Lee said she practiced, can help cut unnecessary calorie intake. Some snacks high in sugar, refined carbohydrates and fat pack a large number of calories into a small serving, and their low protein and dietary fiber content means they may not keep hunger at bay for long.

The relationship between processed food and overall food intake has also been confirmed in clinical trials.

Researchers at the National Institutes of Health published a study in the journal Cell Metabolism in 2019 examining how ultra-processed food consumption affects body weight. Twenty adults were provided with a diet of mainly ultra-processed foods and a minimally processed diet for two weeks each and were allowed to eat freely.

Although the two diets were matched for total calories offered and similar in sugar, fat, carbohydrate and dietary fiber composition, actual intake differed. During the ultra-processed diet period, participants consumed an average of about 500 kilocalories more per day and gained an average of 0.9 kg over two weeks. On the minimally processed diet, they lost an average of 0.9 kg.

The researchers also noted that participants ate faster when consuming ultra-processed foods — a finding that suggests the degree of processing, food texture and eating speed may all influence total calorie intake.

Maintaining weight requires rethinking how snacks are chosen. Rather than eating straight from the bag, portioning out a set amount into a bowl beforehand is advisable, as is checking nutrition labels to compare sugar and saturated fat content. When hunger strikes between meals, choosing nutrient-dense options such as fruit, unsweetened yogurt or a moderate serving of nuts can also help.

Regular exercise plays an equally important role in preventing weight regain.

An analysis published in the journal Scientific Reports in 2026 examined the effect of exercise on weight regain after weight loss. Pooling data from 11 randomized controlled trials involving 568 participants, the researchers found that those who exercised regained an average of 2.81 kg less than the control group.

The US Centers for Disease Control and Prevention recommends that adults get at least 150 minutes of moderate-intensity aerobic exercise per week along with muscle-strengthening activities on two or more days a week. People trying to maintain weight they have lost may need more activity depending on their physical condition and calorie intake.

Aerobic exercises such as brisk walking, swimming and cycling increase energy expenditure, while strength training helps preserve muscle mass during weight loss. Pairing these with adequate sleep, regular meals and periodic weigh-ins can help catch any upward trend in weight early.

Keeping lost weight off over the long term requires consistently maintaining the eating habits and exercise routines that can be sustained in daily life. Even after the weight comes off, adjusting one's lifestyle to account for the body's changed energy expenditure and appetite is the key to preventing regain.


rainbow@heraldcorp.com