Twenty-nine overweight men and women (body mass >25) participated in this six-week outpatient study. The participants were randomized to either a 1500 calorie 40/30/30 diet [40% CHO] (n=14) or a 1500 calorie Step 1 diet [60% CHO] (n=15).
The 40/30/30 diet consisted of 40% CHO, 30% protein, 30% fat, the Step 1 diet consisted of 60% CHO, 15% protein, and 25% fat.
All subjects participated in Universal Circuit Training TM, one hour, three times per week supervised by an exercise physiologist.
All subjects met two to four times (avg.=3) over six weeks with a registered dietitian for review and analysis of compliance to the study diets.
Both groups lost a significant amount of weight (p<0.05) after 6 weeks of treatment (40% CHO, -2.8kg; 60% CHO, -1.2kg).
However, the 40% CHO group lost more weight and a greater amount of body fat (-2.6kg; p<0.05), while the 60% CHO (-1.0kg) group did not achieve significant fat loss.
There were no significant changes for both groups in serum glucose, HgBA1C, total cholesterol, HDL, LDL, or triglycerides during the study.
Profile of Mood States (POMS) for fatigue and vigor was also analyzed in both study groups with the following results: 44% reduction in fatigue (p<0.05) for the 40% CHO group with a corresponding 15.7% increase in vigor (non-significant; p>0.05). The changes within the 60% CHO group did not achieve significance in either fatigue or vigor.
In conclusion, the 1500 calorie 40/30/30 diet resulted in a significantly greater fat and weight loss compared with the 1500 calorie Step 1 diet over 6 weeks.
This is a very compelling argument against the common nutritional mantra that "a calorie is a calorie." Both diets tested were isocaloric, differing only in the macronutrient composition.
The protein-to-carbohydrate ratio in the ?? Diet was 0.75, whereas in the American Heart Association Diet the protein-to-carbohydrate ratio was 0.25.
The fact that exercise was part of the study also eliminated that factor in analyzing the data on weight loss and reduction of body fat.
The fat loss in the participants following the ?? Diet was 260 percent greater than those following the American Heart Association Step 1 diet.
This difference is even more impressive since participants following the ?? Diet consumed 200 percent more fat than the participants on the Step 1 diet.
Furthermore, the fat loss in the ?? Diet was statistically significant (meaning it was reproducible) whereas the in the Step 1 group it was not. In terms of subjective measurents of fatigue reduction and increased vigor, the ?? Diet was again superior to the Step 1 diet. The lack of effect of the ?? Diet on triglyceride levels was probably due to inadequate levels of Omega-3 fatty acids in the diet. Unfortunately, fasting insulin levels were not analyzed in this study (as with other ?? studies) to correlate insulin reduction with loss of body fat.