High Protein Diets



High Protein Diets

Introduction

Many people, from exercise enthusiasts to people who want to lose weight, have used high-protein diets. Some of the popular weight-loss diets with a central theme around high protein intake include the ZONE diet, Protein Power diet, CSIRO diet, and Sugar Busters (Yagami, 2000). The theory behind these diets emphasises the increased satiating effect of protein, with only modest reductions in carbohydrate intake, as opposed to the Atkins diet, which allows for only a small amount of carbohydrates. In general, these diets consist of approximately 30 percent protein as a percentage of energy, 40 percent carbohydrates, and 30 percent fat (Tsai, 2005). Importantly, these diets need to contain protein of high biologic value, or high in essential amino acids, to preserve lean body mass. Moreover, these diets must contain an adequate amount of essential fatty acids, and vitamin/mineral supplements to prevent the development of a malnourished state (Linda, 2005).

Discussion

There are many health benefits to a high-protein diet. In general, doubling the amount of protein as a percentage of energy occurs by reducing the amount of fat and carbohydrate energy with only a 10 to 15 percent increase in the actual amount of protein. Moreover, high-protein diets are associated with better fat loss and relatively less lean mass lost. A study that used a diet similar to that of CSIRO, protein intakes of greater than 1.05 g/kg of actual, rather than desirable, body weight were associated with 1.3-2.6 pound better retention of lean body mass (Clifton, 2001). Therefore, a high-protein diet may ameliorate the loss of lean body mass accompanied by weight loss.

Effects of Protein on Satiety

Many studies have examined the effects of protein on satiety (Xavier, 2006). Typically, studies use a crossover design and presented subjects with one of several preloads of different protein content. Subjective satiety ratings were measured repeatedly for several hours after consumption. In a review of 14 studies, 11 found that the protein preload significantly increased subjective ratings of satiety. Therefore, protein is thought to be the most satiating of the macronutrients, although this does not mean that the other macronutrients should not be consumed in a diet weight loss, because glucose is essential for brain function, and fat plays a role in signaling meal termination (Linda, 2005).

In the same review, of the 15 studies that measured absolute weight loss, seven studies found a significantly greater weight loss with a higher protein diet. Five out of these seven studies had durations of greater than six months as opposed to the studies with null findings. On the whole, diets high in protein may enhance weight loss compared to diets with lower protein in the short term (Tsai, 2005).

Reason of Success of High Protein Diets

A possible reason for the success of high-protein diets may be due to their greater thermic effect. The thermic effect of a food is the increase in energy expenditure above baseline following consumption, or the energy required for digestion, absorption, and disposal of ingested nutrients (Fu, ...