Do "intermittent fasting", "quitting dinner" and "cutting carbs" really work? The new version of the national weight loss guide is here!

Recently, the National Health Commission released a new version of the "Weight Management Guidelines (2024 Edition)" to the public, pointing out that some studies predict that if it is not effectively curbed, the overweight and obesity rate of adults in my country will reach 70.5% in 2030, and the overweight and obesity rate of children will reach 31.8%. How fat is fat? How to lose weight more scientifically? Read on to find out↓↓

What kind of fat is really overweight and obese?

Overweight and obesity are important risk factors for many chronic diseases, including diabetes, hypertension, hyperlipidemia, cardiovascular and cerebrovascular diseases, and certain cancers.

Overweight and obesity are influenced by many factors, including genetics, diet, physical activity level, lifestyle habits, and changes in social environment.

Body mass index (BMI) is a standard for measuring how fat or thin a person is.

BMI = weight (kg) / height (m)²

The normal BMI range for healthy adults in my country is between 18.5 and 24.

A BMI between 24 and 28 is defined as overweight.

Obesity is defined as a BMI of 28 or more. Among them, BMI is further divided into mild obesity, moderate obesity, severe obesity and extremely severe obesity.

At present, it is generally recognized that the way to lose weight is to "control your diet". On the Internet, "light fasting", "quitting dinner" and "cutting carbs" are popular weight loss methods. Do they really work?

Can you really lose weight by not eating staple foods?

In the 1950s and 1960s, there was a popular diet that advocated low-carbohydrate diets. It required limiting high-carbohydrate foods, while allowing free intake of foods rich in protein and fat. Their theoretical basis is that when eating high-protein and high-fat foods, people are more likely to be satisfied and their food intake will decrease. At the same time, due to insufficient carbohydrates, fat cannot be fully "burned" and protein will also be quickly decomposed, so it is difficult for the body to fully utilize the protein and fat eaten.

This diet was very popular among people, mainly because people who used it lost weight very quickly. However, research soon proved that the so-called extra weight loss was just the result of an imbalance in the body's water balance. At the same time, this diet could not be maintained for long, because life without a little starch was really unbearable. So this way of losing weight quickly fell into decline.

In the early 21st century, the modified low-carbohydrate diet quietly revived. A large number of studies have shown that compared with a low-fat, high-carbohydrate diet, a low-carbohydrate diet that provides adequate vitamins and minerals can reduce weight more quickly, without affecting body composition or significantly increasing blood lipids. Some studies have even shown that a high-fat, high-protein diet can improve blood lipids. Against this backdrop, many people have begun to lose weight by not eating staple foods.

The meat goes away quickly and comes back even faster!

People who adopt a low-carbohydrate diet to lose weight usually think that as long as they eat less starch and sugar, skip meals and sweets, and eat vegetables and meat as they please, they can lose weight. Many people have experienced short-term "success" because of this, that is, their weight continues to drop in three months. Unfortunately, their happiness does not last long, because as soon as they start eating staple foods again, their weight will rebound all the way back to the previous level.

Experimental evidence shows that a low-carbohydrate diet can lead to rapid weight loss in the short term, faster than a low-fat, high-carbohydrate diet of the same energy. However, this advantage can only be shown in the short term. In the long term, it has no advantage.

Intermittent fasting to lose weight is actually just a different way of dieting!

We often hear about "intermittent fasting", but what exactly does it mean to not eat: one meal? A few hours? A few days?

It’s no wonder that everyone is a little confused, because “intermittent fasting” is not a rigorous term, and its academic name is a bit confusing: time-restricted eating, intermittent fasting or intermittent energy restriction.

Because the term itself is not rigorous and has no particularly strict and specific explanation, it is like a big basket that can hold anything. Many messy diet plans can call themselves "intermittent fasting."

The popular intermittent fasting diets are mainly divided into three groups: calorie-restricted, time-restricted, and calorie-and-time-restricted. Although they all involve eating less or no food for a period of time, researchers have found that different "intermittent fasting" programs have completely different weight loss effects, and not all of them are useful.

Strict calorie restriction can help you lose weight

A light fasting plan that strictly calculates and limits dietary energy intake, such as the "5 + 2" light fasting plan, which selects two days of dieting out of seven days a week. The amount of food eaten less on the two days must be controlled within 500-600 kcal, leaving an energy gap, which has a certain weight loss effect.

A systematic review article from the University of Freiburg in Germany in 2020 summarized 17 randomized controlled trials of intermittent fasting to achieve an energy deficit and found that intermittent fasting with strict supervision to reduce energy intake could allow subjects to lose about 2 pounds on average after three to five months.

However, this weight loss effect is similar to that of a balanced diet (eating 1/4 to 1/5 less total energy per day).

Just limit the time, maybe it will only reduce loneliness

Other intermittent fasting methods mainly restrict eating time, advocating "eating only during a certain period of time during the day, but eating whatever you want."

It sounds happy, but the weight loss effect is likely to be disappointing.

Scientists specifically found 116 people and randomly divided them into two groups:

Fasting group: Eat within eight hours from noon to 8 pm;

Normal group: normal diet.

The study found that the time-restricted fasting group ate as much as the normal group in a day within eight hours, without eating less. The final result, of course, was that the fasting group did not lose any more weight than the normal group.

In short, after scientists' research, the weight loss effects of various "light fasting" methods can be summarized in two sentences:

Intermittent fasting that only limits time but does not control calories is difficult to lose weight effectively;

Calorie-restricted intermittent fasting can indeed reduce weight, but the effect is similar to eating less at each meal.

Isn’t this just “keep your mouth shut” in another way?

Yes, this is also the essence of weight loss: in order to lose weight, you have to achieve an energy gap, that is, "the energy you eat is not enough", and to achieve this, you either eat less, exercise more, or eat less + exercise more.

The more you exercise, the more you lose weight?

Experts say that the human body is an energy balance body. Simply increasing the amount of exercise without controlling the total amount of daily calorie intake will not achieve the goal of weight loss. In addition, excessive exercise can easily lead to muscle fiber damage, increased intermuscular fat, and thick limbs.

Exercise to lose weight should be combined with one's own characteristics. Generally, obese people should combine aerobic exercise, anaerobic exercise, flexibility and balance training, and should warm up and adjust themselves in time before and after exercise.

Walking, jogging, swimming, cycling, etc. are "low-medium intensity" aerobic exercises that are suitable for most obese people. Children and middle-aged and elderly people can also practice them.

Mountain climbing, rope skipping, rowing, dancing, etc. are "moderate intensity" aerobic exercises, suitable for young people with good physical strength and no serious chronic diseases. It should be noted that patients with knee osteoarthritis are not suitable for this type of exercise.

Young people with good physical strength, middle-aged and elderly people without serious chronic diseases, and patients with mild to moderate osteoporosis can increase muscle strength through most resistance exercises.

Flexibility and balance training such as Tai Chi, yoga, and Pilates are suitable for most people.

Finally, I would like to talk to readers who are willing to try various methods to lose weight:

More and more delicious food and less and less time for exercise make it easier to gain weight.

Losing weight is a health problem that many people have to face. However, losing weight is not just about "completing the task" when the number on the scale becomes smaller, but about developing some good habits that can be persisted.

Don’t let yourself fall into the vicious cycle of “losing weight, stopping and gaining weight back”, and don’t be misled by some exaggerated effects and slogans and become a “guinea pig” for various products and methods.

Source: CCTV.com, Guokr, Dingxiang Doctor