Are High Protein, Low Carb Diets Healthy?

July 29th, 2008 | Posted in Dangers of fast weight loss

In order to understand the dangers of dis-balanced weight loss diets and the sequels they may leave in our body, we have to understand first how the human body transforms various types of foods into vital energy. Each time you choose a diet for losing several pounds or more, you need to seriously weight the benefits with the dangers and to ask yourself if you are prepared to trade your health for a temporary weight loss.

The foods we eat contain three major components:

Proteins:

Found in meat, eggs, milk, cheese, proteins contain 4 kilocalories per gram. Proteins need to be part of the daily diet, because in case the body detects a lack of protein intake, it will consume the protein from the muscle mass in order to supply vital energy, leading to muscle wasting. Various sources (like the RDA – Recommended Dietary Allowance) recommend the daily protein intake to be about 46 grams for women and 56 grams for men (aged 19-70), or between 0.8 gram and 1.4 grams of protein per kilogram of body weight. Of course, physical activity is a factor which needs to be considered, as well as the body’s need for essential amino acids and nitrogen.

Protein deficiency in nutrition may cause poor health, reduced intelligence or even mental retardation.

Protein excess is also a problem, because the body cannot store it in this form, thus converting it into fatty acids or sugars. Nitrogen is removed from the amino acids by the liver, and excreted by the kidneys as urea, in urine. In case of kidney disease, urea can be harmful, and a low protein diet may be recommended.

Proteins are amongst the most widespread allergens, thus causing a big number of food allergies.

Carbohydrates (or carbs)

Carbohydrates are biomolecules which have the role of storing and transporting the energy in the body. Their digestion requires less water than the digestion of proteins or fats. Carbs are not essential nutrients, because the human body can take all the needed energy from proteins and fats. Carbs contain 3.75 kilocalories per gram and they can be found in foods such as bread, pasta, cereals, beans, potatoes or rice.

Carbs are classified by dietitians and nutritionists in two major groups: simple and complex. The Dietary Guidelines for Americans, published by USDA in 2005, gives up this simple – complex classification of carbs, instead recommending fiber-rich foods and whole grains to be consumed for the daily carb intake.

Lipids (fats)

Lipids are very important for a healthy nutrition. While some of them are essential for life, others may be harmful and may be risk factors for heart diseases (like cholesterol, in the case of hypercholesterolemia). Fatty acids are also lipids, and scientists believe that the human body needs essential fatty acids such as omega 6 and omega 3 fatty acids. They are contained in fish oil, and this is why many specialists recommend fish consumption at least three times a week.

Besides the risk of obesity, a high fat intake seriously increases risk for major illnesses, such as diabetes or atherosclerosis. Atherosclerosis consists of plaque building up on the inner walls of the arteries, thus generation coronary and cardiovascular diseases like heart attacks or strokes.

What Happens During Low Carb, High Protein Diets

As you’ve already seen, a low level of carbohydrates in nutrition is not a problem for the body, as carbs are not essential nutrients. However, in case you suffer from kidney diseases, you shouldn’t go for high protein diets, because your body would encounter problems in urea excretion.

A study published by the University of Washington School of Medicine, Seattle, in 2005, shows that the anorexic effect of protein may contribute to the weight loss produced by low-carb diets:

An increase in dietary protein from 15% to 30% of energy at a constant carbohydrate intake produces a sustained decrease in ad libitum caloric intake that may be mediated by increased central nervous system leptin sensitivity and results in significant weight loss. This anorexic effect of protein may contribute to the weight loss produced by low-carbohydrate diets.

(Sopurce: PubMed – indexed for Medline)

So, it seems that high-protein diets really help people lose weight. However, there’s another study, published in 2007 in the European Journal of Clinical Nutrition, done by Professor A. Trichopoulou and his colleagues at Department of Hygiene and Epidemiology, University of Athens Medical School, which aimed to assess the relationship between long-term weight control with low-carb-high-protein diets and mortality. Conclusions of this study done on a sample of adult Greek population:

Prolonged consumption of diets low in carbohydrates and high in protein is associated with an increase in total mortality.

As you can see, the issue of choosing a healthy weight loss plan is more complex than it seems at first glance. This is why a specialist’s advice is priceless and why a bit of research on how our body works can help us understand how easy it is to harm ourselves even with simple wishes such as to get rid of 5-6 pounds to look better.