Studies have shown that the efficacy of low-carb diets could be due to their high protein content, hence researchers question whether raising protein intake could actually help fight obesity.
In a recent study researchers set out to test the hypothesis that increasing protein while maintaining carbohydrate intake decreases the appetite, leads to the consumption of fewer calories and results in weight loss. However some are of the opinion that preventing weight gain is a more complex matter than simply telling people to eat less and exercise more.
For the sudy19 subjects followed three different diets, one after the other. For the first two weeks, they followed a weight-maintaining diet where protein accounted for 15 percent of calories, fat 35 percent and carbohydrate 50 percent. For the second two weeks, they followed an isocaloric diet that was 30 percent protein, 20 percent fat and 50 percent carbohydrate. Finally, for 12 weeks they followed a diet where there was no restriction on calories but the proportions, again, were 30 percent protein, 20 percent fat and 50 percent carbohydrate.
Their appetite, caloric intake, body weight, and fat mass were measured throughout, and at the end of each phase blood samples were taken to measure insulin, leptin (the hormone responsible for satiety) and ghrelin (the hunger hormone). Researchers say they found that satiety was 'markedly increased' with the isocaloric diet but leptin was unchanged.
With the ad libitum high protein diet, the participants average spontaneous calorie intake decreased by between 376 and 504 per day, their body weight decreased by between 4.4 and 5.4 kg and their fat mass decreased by 3.3 to 4.1 kg. Leptin levels 'significantly decreased' during this phase and ghrelin increased. As carbohydrates remained at 50 percent during all three phases, the effects of the ad libitum diet would appear to be due to the high protein intake.
Researchers say that the high protein content of weight loss approaches like the Atkin's Diet and The South Beach Diet may actually be due to the satiating effects of their high protein content (30 to 40 percent of calories
consumed) rather than the low-carbohydrate design.
However specialists say they are unsure whether to recommend that obese and overweigh people increase their protein intake from 10 to 20 percent of calories to 20 to 30 percent due to the potential adverse effects associated with a high protein diet. The trouble being that many of the sources of protein consists of substances such as red meat, cheese and whole milk which are also high in saturated fats. And saturated fats are known to raise LDL 'bad' cholesterol levels.
Hence researchers say it is preferable to replace sugars from soft drinks with protein from low fat milk, high-fat milk and dairy products with the lean versions, and possibly white bread and pasta with lean meat, without reducing the intakes of fruit, vegetables and whole-grain products.
According to a recent survey it was found that private spending in America on obesity-related health care increased tenfold between 1987 and 2002, from $3.6 to $36.5 billion. However if protein could be the key to bringing the obesity epidemic to its knees, is a question still left unanswered.