Lifestyle+ — 6

The emergence of the term carbotoxicity conveys the multiplicity of risks associated with excessive intake of carbohydrates. As with everything, moderation is the ticket: both low, less than 40 percent, and high, greater than 70 percent, daily caloric intake are associated with increased all-cause mortality. Much of the relationship can be affected by the type of carb, with good comprising resistant starch and other high-quality carbs in the form of dietary fiber. From 185 prospective studies, 58 randomized clinical trials, assessing dietary fiber of 25–30 grams per day, there was an association with a 15–30 percent reduced all-cause and cardiovascular mortality, type 2 diabetes, and colon cancer.

In contrast, low-quality carbs are fast-digesting, like the sugars we’ve covered. They also include potato products, or refined grains, which are a high glycemic load, raising insulin levels and predisposing to weight gain. A high glycemic index diet among more than 137,000 people ages thirty-five to seventy years on five continents was associated with more than a 25 percent increase in cardiovascular deaths. Good, unprocessed carbs of nonstarchy vegetables, legumes, fruits, and whole grains are the ones to give priority.

Much of the current guidance via the National Academies’ Recommended Dietary Allowance (RDA) for protein intake is based on relatively scant evidence, mostly from short-term nitrogen balance studies in young adults, underestimating what is needed in older individuals and longer term. The recommended daily intake of protein is 0.8 gram per kilogram of weight, 11 percent of total energy. You can get your somewhat personalized Dietary Reference Intakes calculated; my US Department of Agriculture recommendations are shown in the table below (vitamins and minerals are not listed). When I put in parameters for a much younger man, the output didn’t change very much, and the estimated daily caloric needs is highly influenced by your input of “active” or “very active.” The protein RDA is remarkably low, and that will not help prevent loss of muscle mass with age—by age eighty, the average person will lose eight kilograms of muscle from their peak. The evidence suggests that for older adults, higher protein intake is needed, but the optimal amount is unknown.