Health

There is no difference between diets high or low in fat

07/25/2012

 


A calorie is really just a calorie? The calories in a soda cause the same effect on your waistline than the calories of an apple or a chicken fillet?
For decades these questions puzzled researchers and also those who diet.
 
Last month, they gained new prominence to a study published by the Journal of the American Medical Association, suggests that after losing weight, people with a diet rich in fat and protein burning more calories than people who consumed more carbohydrates.
Questioned Jules Hirsch - Professor and chief medical officer emeritus of Rockefeller University, and obesity researcher for nearly 60 years - about the current state of research in the area. Hirsch, who receives no money from pharmaceutical companies or health food industry, wrote some classic works that explain why it is so difficult to lose weight and because it usually returns.
NYT: The study of the Journal of the American Medical Association has called attention. People should do diets high in fat and protein if you want to lose weight?
Jules Hirsch: In the study, they underwent 21 people on a diet that made them lose between 10% and 20% of its weight. Then, after the weight is balanced, they underwent a subject to these three different diets maintenance. One was low in carbohydrates and high in fat, that is, was basically the Atkins diet. The other was the opposite - high in carbohydrates and low in fat. The third was a middle ground between the two. Further, they measured total energy expenditure - the calories burned - and resting energy expenditure.
They reported that people who were subjected to the Atkins diet were burning more calories. So that was a good diet. This type of low-carbohydrate diet generally enables a higher initial weight loss, compared to diets containing the same number of calories, but with other carbohydrates. This is because when levels are low carbohydrate and high fat on a diet, people lose water, which can hamper the calculation of total energy expenditure.
 
As usual based on the number of calories per unit of lean body mass - the body part is made of fat. When losing water, the lean body mass decreases, and the number of calories by increasing lean body mass. It is pure mathematics. There is no abracadabra that would bring immediate benefits to those who submit to a diet. This person will lose water, but no fat.
The study gave no information on how the calculations were made, but this is one possible explanation for the results.
NYT: You mean the whole thing may just be an illusion? All that happened was that these people temporarily lost water when submitted to high protein diets?
Jules Hirsch: I think the most important illusion is the belief that a calorie is a calorie, and everything depends on the amount of carbohydrates consumed by one person. There is an immutable law of physics in action - the energy consumed is necessarily equal to the number of calories dispensed by the system when stored fat is unchanged. Calories leave the system when the food is used as fuel for the body. To decrease the amount of fat - that is, reduce obesity - is necessary to reduce the number of calories consumed to increase caloric expenditure with more physical activities, or do both. This is a universal truth, no matter whether the calories come from pumpkins, peanuts or foie gras.
To believe otherwise is the same as imagining that we can actually find a perpetual engine that works to solve our energy problems. That will not happen, and change the source of calories does not allow us to disobey the laws of physics.
NYT: Did you ever wonder if people react differently to diets with different compositions?
Jules Hirsch: Dr. Rudolph Leibel - currently Obesity Research at Columbia University - and I selected normal-weight people and we live in a hospital, where we calculate the number of calories they receive every day, so keep absolutely constant weight, something very difficult to accomplish. For this, we used liquid diets with an exact number of calories.
We kept constant the number of calories, always giving research subjects the required amount to keep them exactly the same weight. However, we vary dramatically the proportion of fat and carbohydrates each diet. Some of them contained virtually no carbohydrate, while others contain almost no fat.
Q: What happened? Some of these people gained or lost weight unexpectedly, while receiving diets with the same number of calories but with different compositions?
Jules Hirsch: No, there is no difference between diets high in fat and poor.
Q: Why is it so hard to lose weight?
Jules Hirsch: What your body does is calculate the amount of energy available for emergencies and for everyday use. The stored energy is the total fat in your body. Now we know that there is a countless amount of hormones that are always measuring the amount of fat you have. His body is taken to eat more or less according to this mechanism.
Q: But if we have such a mechanism, why people today are more obese than in the past?
Jules Hirsch: This wonderful mechanism involves genetic and environmental factors and is set early in life. It is unclear how much of the adjustment is made soon after birth and how much is done by feeding and other influences early in life. There are many possibilities, but we still do not know.
NYT: It means that something happened in the first years of life of each person to adjust your body to require more fat in your body?
Jules Hirsch: Yes
NYT: What would you say to people wishing to lose weight?
Jules Hirsch: I counsel them to choose a diet with fewer calories. They should eat what ever eaten, but in smaller quantities. This needs to be carefully calculated. People must eat the minimum needed to live well and should do more exercise.
NYT: There is no magic diet, or at least preferred a diet?
Jules Hirsch: No. Some diets may be best for medical reasons, but not for weight control. People invent new diets all the time - after all, why not eat pistachios midnight when the moon is full? We've seen all kinds of diet imaginable. But still, people always invent something new.
 


Source: Ig

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