High-Protein, Low-Fat, Low-Carb Diet

A high-protein, low-fat, low-carb diet, also known as a protein sparing modified fast or PSMF, is a type of very low calorie diet in which almost all your calories come from protein. Both carbohydrate and fat intake is usually restricted to 20 g a day or less. Originally, this type of diet was reserved for morbidly obese patients who needed to lose a large amount of weight in a short period, due to either serious health risks or upcoming surgery. Today, both athletes and regular people use this type of diet. Due to the intensity of this diet, you must get clearance from your doctor before attempting it.

Mechanism of Action

A high-protein, low-fat, low-carb diet works by forcing your body to use a large percentage of body fat for its daily energy requirement. Because carbs are restricted, your body has to burn fat to function. The dietary fat restriction forces your body to use its stored fat. A large amount of protein, usually 1 to 2 g per 1 kg of lean body mass, helps prevent the breakdown of muscle tissue.

Evidence

Numerous research studies have confirmed that a high-protein, low-fat, low carb diet is significantly more effective at producing rapid weight loss than traditional diets, especially in insulin resistant patients. A study published in the March 1987 issue of "International Journal of Obesity," found that those on a very low calorie PSMF lost significantly more weight then those on a balanced 1,200-calorie diet plan. It also noted that the patients on the PSMF were less hungry than the other group, even though they also ate less. This study confirm the findings of a study published in the January 1980 issue of "The Journal of Pediatrics," in which the average weight loss in a four-week period was 15.6 lbs. No muscle breakdown was noted. A study published in the August 2010 issue of "Journal of Pediatrics" determined that high-protein, low-fat, low-carb diets were effective at treating obesity in children and adolescents.

Benefits

The biggest benefit of a high-protein, low-fat, low-carb diet is your ability to maintain muscle mass despite intense caloric restriction. This quality is unique to this kind of diet, according to an August 2010 study published in "The Journal of Pediatrics," which found that both high-protein, low-carb diets and low-fat diets caused muscle tissue to break down. A PSMF also allows you to lose a larger amount of weight than traditional dieting, about 3 to 5 lbs. a week, depending on your starting weight. This is especially significant because almost all of the weight lost is from body fat.

Adverse Effects and Precautions

Although effective, this type of diet can have man side effects, especially if you stay on it long term. Headaches, fatigue, myalgia, abdominal pain, nausea, dizziness, sleep disturbances and bad breath are the most commonly experienced adverse effects. It's also possible to experience "rabbit starvation" while on a high-protein, low-fat, low-carb diet -- a syndrome characterized by vomiting, low blood pressure, severe muscle weakness and arrhythmias. This occurs if you take in too much protein without taking in fat or carbohydrates. You can help prevent rabbit starvation by taking fish oil supplements every other day while on the diet to get the required essential fatty acids.

Some people should not attempt this kind of diet. A high-protein diet can strain the liver and kidneys, which makes a PSMF a contraindication in people with liver or kidney disease. The lack of fiber you take in on this diet can cause or aggravate conditions such as constipation and diverticulitis, according to the MayoClinic.com. For people with certain genetic conditions,such as N-acetylglutamate synthase deficiency or acute intermittent porphyria, this diet can be dangerous and even life-threatening. That's why it's important to check with your doctor before embarking on this kind of diet.

References

• "The American Journal of Clinical Nutrition"; Introduction to Protein Summit 2007: Exploring the Impact of High-Quality Protein on Optimal Health; Nancy R. Rodriguez, et al.; May 2008
• "International Journal of Obesity"; Less Food, Less Hunger: Reports of Appetite and Symptoms in a Controlled Study of a Protein-Sparing Modified Fast.; T.A. Wadden, et al.; March 1987
• "The Journal of Pediatrics"; Consequences of Modified Fasting in Obese Pediatric and Adolescent Patients. I. Protein-Sparing Modified Fast; Russell J. Merritt, et al.; January 1980
• "The Journal of Pediatrics"; Efficacy and Safety of a High Protein, Low Carbohydrate Diet for Weight Loss in Severely Obese Adolescents; Nancy F. Krebs, et. al.; August 2010
• "Pediatric Diabetes"; Recent Advances in the Treatment of Childhood Obesity; R.M. Suskind, et al.; March 2000
• MayoClinic.com; High-Protein Diets: Are They Safe?; Katherine Zeratsky; June 2010