Magazine article Nutrition Health Review

Are Protein Diets a Safe Way to Lose Weight? an Interview with Maria Westberg, R.D

Magazine article Nutrition Health Review

Are Protein Diets a Safe Way to Lose Weight? an Interview with Maria Westberg, R.D

Article excerpt

Q. What is a protein?

A. Protein is found in animal products, and vegetables also have some protein. Protein is made up of amino acids, which are essential to our body's functions of tissue building and repair. Because we cannot make enough amino acids ourselves, we need to eat protein to get "complete" amino acids. Whether the protein is vegetable-derived or animal-based, we need to eat it.

Q. Is there a difference between animal and plant protein?

A. Yes, there is. Vegetable, or plant, protein generally is not complete, so it would not have all of the amino acids there; you would need to combine it with another vegetable protein, and that would complete that protein. For example, rice with beans is a common combination that gives you a complete protein; the rice has a little bit of protein, as do the beans, and together they complement each other.

Q. What is a carbohydrate?

A. A carbohydrate is sugar, basically. It is found in almost everything except in foods that are just protein or just fat. So fruits, vegetables, whole grains, and grains all have carbohydrates in them. There are different types of sugar. There are whole grains, and there are more refined sugars. A carbohydrate gives 4 calories per gram, just as a protein does.

Q. What is the definition of a high-protein diet?

A. The recommended amount is 0.8 grams per kilogram of body weight; about 15 percent of our calories should come from protein. I would consider a high-protein diet to consist of 30 percent protein or more.

Q. What are the inherent dangers of a high-protein diet?

A. If you are eating a high-protein diet and are not getting enough sugar in your diet, that could lead to ketosis, a process whereby the body is breaking itself down for sugar. It is not an ideal situation; the brain's preferred source of fuel is sugar. The body can break down muscle and fat into sugar, but it prefers to get it from the diet. So if you are not eating enough of the other substances, the other nutrients, that's the danger.

If you eat a lot of protein, you need more water and more fluid intake, because it takes more fluid to digest the protein. You lose more fluids as well with a high-protein diet. Dehydration is a risk.

The big thing is the long-term risk; we don't have any long-term clinical studies on this diet, so we don't know for sure. A high-protein intake does put a lot of stress on the kidneys because these are the organs that have to digest it all and cycle it out. A lot of extra protein goes out in the urine; thus, this can stress the kidneys. For people with kidney disorders, kidney disease, or diabetes, a high-protein intake is more of a risk, but otherwise we don't really know the long-term dangers.

Q. How does too much protein affect the kidneys?

A. Too much protein really overworks the kidneys and can lead to kidney stones, as well, for people who are predisposed to them. Extra urinary calcium secretion can end up as kidney stones.

Q. Is a high-protein diet derived from plants as dangerous as one derived from animals?

A. I think that it would be really difficult to have a high-protein diet derived just from plants, just because the plants do not provide as much protein as animals, per serving. For example, even with soy milk or tofu [bean curd], I think that it would be hard to make it completely high protein. But if you were able to make a high-protein diet that was plant-based, I don't think it would be as dangerous because you don't have all the saturated fat that an animal-based diet would have.

Q. What is the theory behind an increase in protein and weight loss?

A. For one thing, the immediate weight loss you see is mostly water loss, and that can be as much as 10 percent of your weight that you could lose in water after a few days on a high-protein diet. I think that the people who do see a real weight loss after following a high-protein diet are definitely consuming fewer calories and are cutting out other sources of calories in the diet. …

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