Since 1975, the number of obese people worldwide has tripled, and today 1.9 billion adults worldwide are considered overweight, and the number of deaths caused by this situation far exceeds the number of underweight and malnutrition. National Health Insurance System One of the biggest cost burdens (NHS) is that 70% of adults in the UK are expected to be at risk of being overweight or obese by 2034.
Obesity is a problem in the body's energy balance. If a person consumes more calories than the calories they consume, then the difference will be in the form of body fat, but the first thing that needs to be determined is the imbalance between intake and expenditure. The reason why there is no control system in the human body can help control the amount of food the body needs to eat, so understanding the answer to this question may be expected to help scientists solve the problem of obesity.
There are a lot of explanations about why people sometimes get too much calories, which usually surrounds a lot of nutrients in people's daily diet. A lot of nutrients include fat, protein and carbohydrates. One of the explanations for excessive calorie intake. It is the 'protein utilization hypothesis'. This hypothesis is that people mainly consume foods with high protein content. If the protein level is proportional to the level of fat and carbohydrate, people will ingest it in order to meet the daily protein needs of the body. Excess calories.
Another option is the 'carbohydrate-insulin model', in which carbohydrates can make the body fatter, because when we eat, carbohydrates stimulate the production of insulin, which promotes the storage of carbohydrates in the form of fat and stimulates the body. The 'hunger' to get extra dietary intake, and now with the rise of the high-fat, low-carbohydrate (HFLC) diet, this idea has become very popular.
However, the traditional view is that what makes us fat is the body's intake of fat, because fat stimulates the reward and punishment center in the brain, which encourages us to eat more. This is the hypothesis called 'hyperpoly'.
Man and mouse
You might think that testing between these ideas is quite straightforward, that is, simply letting people touch different diets to see who gets fat, but researchers may not be able to get randomized controlled clinical trials in the human body. Because ethically speaking, it is unacceptable for any person to accept that the expected result is severely obese or harmful to their health. Therefore, the best thing a researcher can do is to test it in an animal body such as a mouse. To observe the results, and to provide some clues for research in the human body, the researchers recently conducted a corresponding test on 1000 mice, the researchers fed these mice with 30 different diets for 3 months (equivalent 9 years of humanity).
The 12 diets included in the study varied between 5% and 30% protein, and the fat content of the 12 diets ranged from 8.3% to 80%. The design of this fat component mimicked The diet structure of the average American, the sugar content of all diets remained unchanged at 5%. In the previous six diets, the researchers kept the fat and protein content unchanged, and the sugar content was between 5% and 30%. Five different groups of mice were studied, one group of mice was more likely to be obese or tolerant to obesity; the researchers measured the food intake and body weight of the mice daily, and used MRI to measure the body of the mice every week. Fat content.
The researchers said that changing the level of protein had the least effect on total caloric intake and body fat in mice. When the researchers fixed protein and fat levels, the change in sugar intake in mice did not seem to have a significant effect on body fat. Perhaps because other carbohydrates in the diet are highly refined, the higher the levels of these carbohydrates, the more protective they are against weight gain, and weight gain may not support the carbohydrate-insulin model.
In fact, the only way to make a mouse fat is to let it eat more fat through the diet, but this relationship is not linear, in the case of a diet with a fat content of 50%-60%, The more food a mouse consumes, the more weight it gains. However, when the fat content is higher, the body weight may increase less. The weight of mice with 80% fat in the diet increases with 30% fat. The mice gained roughly the same amount of weight, and the researchers didn't know why. In these high-fat diets, mice consumed less calories and did not increase their body weight.
Analysis result
There are still many limitations in this study. The key point is that these laboratories are performed in mice. Although the researchers have a lot of knowledge about the genetic and physiological characteristics of mice, the response of mice to humans may be different; In terms of consideration, researchers may not be able to experiment in the human body, so they can only rely on multiple pairs of mice to conduct relevant research to obtain relevant evidence.
Researchers only use sugar as part of the diet of mice, but some studies believe that adding sugar to drinking water may have a greater impact on the body fat of rodents, the researchers said, if the study from mice Data can be transformed into human studies. If you are thin and want to avoid getting fat, the best strategy is to control the fat in your diet to less than 20% of total calories; when the sugar content in your diet reaches 30% of total calories, perhaps It's not a big problem, but it may be a big health problem in liquid form, and protein seems to have no effect on the health of the body.
The research results obtained by the researchers only apply to individuals who are already very thin and want to avoid weight gain. For people who are already obese, whether this is the best strategy has not been confirmed by relevant research institutes, but Fortunately, this may be something researchers can do in human clinical trials.
