Since the discovery that calorie restriction increased lifespan, many studies have been performed including studies with non-human primates; all with overwhelming evidence. However, the mechanism by which lifespan increases through calorie restriction, has eluded researchers.
Data on the physiologic effects of caloric restriction in rhesus monkeys resembles rodent studies demonstrating reduced body and fat mass, lower blood glucose, insulin, leptin, free T3 (decreased body temperature), and serum triglycerides. Interestingly, centenarians have lower blood glucose, insulin, leptin, free T3 and serum triglycerides than those who do not live to be over one hundred years old. One can conclude, the fundamental mechanism by which calorie restriction improves lifespan appears to alter these metabolic factors.
A new study analyzed the data from patients attending a private practice. These patients were referred for the treatment of diabetes, cardiovascular disease, overweight, fatigue, and other chronic diseases of aging.
The diet:
? Calories were not explicitly restricted; patients were told to eat when they were hungry.
? Recommended sources of fat included; raw nuts, seeds, avocados, olives, olive oil, flax oil, and cod liver oil.
? Protein intake was limited to 1.0g/kg of lean body mass. If the subjects exercised it was increased to 1.25g/kg.
? Recommended sources of protein included sardines, fish, eggs, tofu, chicken, turkey, wild meats, low fat cheeses, seafood, and vege burgers.
? Carbohydrate sources included only non-starchy fibrous veges; lettuce, greens, broccoli, cauliflower, cucumbers, mushrooms, onions, peppers, etc.
The average daily macronutrient intake ended up being 20% carbs (most of which was fiber), 20% protein, and 60% fats.
The results: Serum insulin decreased by 48 percent, leptin decreased by 8 percent, fasting glucose by 40 percent, triglyceride by nearly 8 percent, and free T3 by almost 6 percent.
The key factor in this study is the participants were not limited in the amount of food they could consume. The researchers wanted to focus on the types of foods or macronutrients that would result in improved health and a longer life.
