According to the laws of physics, no matter whether the calories come from carbohydrates, fats, or proteins, they cannot disappear into thin air after eating. How can we say that protein will not be turned into fat and stored?
From carbohydrates to fat: lipid regeneration
Have you, readers, ever wondered where that ring of fat on your belly comes from?
In addition to the obvious answer "it's all from what you eat", we can classify the sources of body fat into two categories:
-Storage dietary fat directly.
- Convert carbohydrates into fat and store them.
Let me give you a guess, do we get more fat in our stomachs from eating directly, or does it come from rice (carbohydrates)?
As shown in the picture above, only a very small amount of body fat is synthesized from carbohydrates. Most of the starch eaten is either converted into glycogen and stored in the liver or muscles, or is burned.
Even if we go to the extreme route and force people to eat excessive carbohydrates every day, the rate of fat synthesis is still very low. Past studies have shown that with a high carbohydrate intake of 300-400 grams per day, only 9.3 grams will be synthesized into fat.
In short, it is not easy for carbohydrates to turn into fat.
This is also the basis of the low-fat diet: since carbohydrates are difficult to convert into fat, eating more starch will definitely not make you fat. Unfortunately, this theory ignores one thing: although carbohydrates do not directly increase fat mass, they can inhibit fat burning. This requires another complete blog to explain.
At least we know very well that low-fat does not mean that you will not gain weight.
From protein to fat: a longer biochemical path
Back to today’s topic: Is it possible for protein to be synthesized into fat?
Of course it is possible! And it has more than one path to take.
The picture above is the structure of a general amino acid.
If we erase the red amino group on the left side of the amino acid, we can use the remaining C (carbon molecule) to make glucose, acetyl-coenzyme A (Acetyl-CoA) and other things with weird names. Glucose can enter the above-mentioned lipid neogenesis pathway, and acetyl-CoA can be used to directly synthesize fat.
In other words, it is entirely possible to use protein (amino acids) to synthesize fat.
But even if protein can really turn into fat, the amount should be extremely small.
When people eat a lot of protein, the rate of amino acid oxidation in the body will increase, and the rate of protein synthesis will also increase. To put it bluntly, excess protein is either burned or synthesized into body tissue.
Even if some fish slip through the net and are converted into glucose or acetyl-coenzyme A, they still have to go through the already difficult process of lipid regeneration before they can become fat.
That’s why we make such a bold statement: Eating protein (relatively speaking) makes it less likely to gain weight.
But this is not my final say. Is there any human experiment to prove it?
High protein diet research
The first article was published in the famous medical journal JAMA in 2012. American scholar Bray recruited 25 adults and "confined" them in the laboratory for 10-12 weeks.
After first confirming the weight and daily caloric requirements of each subject, the research laboratory began to provide meals that exceeded the basic value by 40%. In other words, if you originally eat 2,000 calories a day, you canBoys who maintain their weight now need to eat 2,800 calories a day.
They don't have the freedom to decide how much to eat. If they don't eat, they have to pack up and leave.
The subjects were then randomly divided into three groups and given meals with varying protein amounts of 5%, 15%, and 25% respectively.
What changes happened to their bodies
At first glance, it seems that the more protein you eat, the more you will gain weight. But if we look a little closer...
Statistically, there was no difference in fat gain between the three groups.
But the muscle mass is much worse (Note 3). A medium-to-high protein diet can still increase muscle mass without exercise. The low protein group did not increase but decreased, and was significantly worse than the other two groups.
What’s more interesting is that the resting and total caloric consumption of the medium-high protein group increased significantly.
In another 2015 study, Bray repeated this result and found that these extra calories consumed came from muscles, liver, and kidneys.
Bray wrote directly in the abstract of the paper: "In a strictly monitored environment, increasing total caloric intake will increase body fat accumulation. Protein intake will only affect muscle mass and metabolic rate, and has nothing to do with fat formation."< /p>
Seeing this, some readers may be dissatisfied: the high-protein diet group gained more muscle and increased their basal metabolic rate, which is good and true, but they still gained three kilograms of fat!
After all, some of the extra calories the subjects ate included carbohydrates and fats, so it is difficult for us to independently analyze the effect from protein.
It’s time for the next piece of research.
Research on whey protein binge drinking
American scholar Antonio and others published the results of their high protein research in the International Journal of Sports Nutrition in 2014.
Antonio recruited 30 young people who usually trained heavily and divided them into two groups: the control group maintained their usual diet and training pattern, and the high-protein group, in addition to maintaining the above habits, also had to increase their daily protein intake. Increase to 4.4 grams per kilogram of body weight.This is approximately 5 times the recommended value in current dietary guidelines.
It is difficult for readers to understand when talking about numbers, so let’s assume:
Assuming your current weight is 85 kilograms, 4.4 grams per kilogram of body weight means that you need to eat 374 grams of protein every day, which requires 53 eggs, 12 slices of chicken breast, or 47 ounces of steak. And don’t forget, you must maintain your past fat and carbohydrate intake.
Fortunately, there is a wonderful invention called whey protein in this world, which allows this inexplicable research to be completed. Scoop up a spoonful and add it to water, and you can easily drink about 20 grams of protein in one breath.
These subjects ate (drank) more than 140 grams of protein every day. What changes occurred in their weight?
The answer is: no change
You heard it right, whether it is the control group or the high-protein group, there is no statistical change in weight, body fat, and muscle mass, and there is no difference between the groups.
Won’t eating protein make you fat? Don’t worry, this study has several inherent limitations that prevent its conclusions from being 100% trusted:
First, unlike the previous study where Bray cruelly locked up subjects, this study was a study of free movement and eating. We cannot say whether the subjects actually drank whey as instructed or maintained their original lifestyle.
Second, they drink whey protein instead of getting it directly from food. Does this conclusion apply to egg and steak lovers? We have no way of knowing.
Third, this study recruited practitioners with heavy training habits. Can the same conclusion be replicated in friends who are obese and have no exercise habits? Big question mark.
However, judging from the current evidence, if readers are determined to eat a lot, choosing high-protein foods "should" be less likely to make you explode like a balloon.