Regardless of what you are told, the only way to lose excess body fat is to eat fewer calories. I have long talked about the benefits of calorie restriction as a way to improve your cardiovascular health thereby improving your healthspan as well. (1-3). A recent analysis of CALERIE (Comprehensive Assessment of Long term Effects of Reducing Intake of Energy), a study looking at two years of prolonged caloric restriction in healthy individuals, found this to be true in “normal weight” subjects (4). I say “normal weight” because although their average BMI was 25, their percent body fat was 33 per cent which is considered to be obese (greater than 25 percent for males and greater than 32 per cent for females). Although they tried to reduce their calorie intake by 25 percent for the two-year study, the best they could achieve was about 12 per cent. This means the calorie-restricted group was eating about 300 fewer calories per day for two years.
A couple of surprising things from the study. First, nearly all the change in weight took place in the first six months with very little change in the next 18 months even with continued calorie restriction. This is typical of most controlled calorie-restriction programs like the long-term Pounds Lost studies at Harvard (5). Likewise, it appeared that most of loss of body fat happened in this same time period. At the 12 month mark, individuals had lost on average 13 pounds of fat, but more than 10 pounds of muscle mass. The loss of body fat was due to the restriction of calories, but the loss of muscle mass was due to protein restriction. Total protein intake went from an average of 102 grams of protein per day to 89 grams of protein per day. At 24 months, muscle mass hadn’t been regained, but individuals had gained back about 2 pounds of fat. Although the calorie-restricted group had lower insulin levels, the change in their fasting glucose levels was virtually the same as the control group. This is because muscle is the primary site for taking glucose out of the blood, and if you lose muscle mass, then glucose levels in the blood don’t go down even though you are consuming fewer calories.
Nonetheless, those in the calorie-restricted group did see their blood pressure and blood lipids decreased. However, all of these changes occurred in the first year with virtually no changes in the second year of the study. The only parameter that continued to change in the second year compared to the first year was a continued reduction in inflammation as measured by C-reactive protein. What this means is that most of any weight loss, fat loss, reduction in blood pressure, blood lipids, as well as blood glucose levels are all likely to take place in the first six months of any calorie restriction program. That’s not encouraging news. But the continued drop in inflammation with calorie restriction is great news because that is the real cause of both a decreased healthspan as well as lifespan.
This is why Zone Pro-Resolution Nutrition offers an even greater potential for health care in the future. The Zone Diet is a calorie-restricted diet, but unlike the CALERIE study the Zone Diet contains adequate protein to not only maintain muscle mass, but also to improve satiety. However, as we have shown clinically, when using the new generation of Zone Protein as a significant source of your total protein, you gain muscle mass instead of losing it (6). But the real benefit of following the Zone Diet for a lifetime is the continued reduction of inflammation that can be greatly accelerated by the addition of high-dose omega-3 fatty acids to speed up the resolution of any existing inflammation. Finally, by adding high-dose polyphenols, you can further active the gene transcription factor AMPK that repairs tissue damaged by inflammation. All of this is detailed in my new book, The Resolution Zone, that will be available shortly (7).
Increasing your intake of omega-3 fatty acids and polyphenols (along with calorie restriction) can also help you finally reach the Zone. Once you're in the Zone, then you know you have done everything possible to optimize your body’s internal Resolution Response which is the real key to future of medicine.
- Sears B. The Zone. Regan Books. New York, NY (1995)
- Sears B. The Anti-aging Zone. Regan Books. New York, NY (1999)
- Sears B. The Anti-Inflammation Zone. Regan Books. New York, NY (2005)
- Kraus WE et al. “2 years of calorie restriction and cardiometabolic risk.” Lancet Diabetes Endocrinol DOI.org: 10.1016S2213-8587(19)30151-2 (2019)
- Bray GA et al. “Lessons learned from the POUNDS Lost study: genetic, metabolic, and behavioral factors affecting changes in body weight, body composition, and cardiometabolic risk.” Curr Obes Rep. 8: 262-283 (2019)
- Johnston CS et al. “Use of novel high-protein functional food products as part of a calorie-restricted diet to reduce insulin resistance and increase lean body mass in adults: A Randomized controlled trial. Nutrients 9: E1182 (2017)
- Sears B. The Resolution Zone: The Science of the Resolution Response. Zone Press. Palm City, FL (2019)