How to be a Centenarian: Calorie-restricted Diets’ Impact on Lifespan

Continuing our series of blogs aimed at empowering via knowledge, we will discuss how diet plays a crucial role in influencing longevity, with numerous studies highlighting the correlation between what we eat and how long we live. While no long-term studies have proven the benefits of calorie restriction on human lifespan, shorter-term studies suggest that it improves health and increases lifespan. Caloric restriction without malnutrition extends lifespan by inhibiting the “Target Of Rapamycin” enzyme (TOR). When food is abundant, TOR activity increases, prompting the cells in our body to divide and grow. If there is less food, TOR instructs the body to be alert, a state that scientists call a “mild stress response.” Consequently, when TOR detects food scarcity, it shifts the body into conservation mode, slowing cell division. This conservation mode also triggers a process called autophagy, which is like a “cellular clean-up,” where our body realizes there isn’t much food around and starts rummaging through our cells, looking for anything we don’t need—defective proteins, malfunctioning mitochondria, and other stuff that isn’t working anymore—and cleans the house. Our body clears out all the junk and upcycles it into fuel, renewing our cells. (nutritionfacts.org)

Dr. Greger’s research suggests that the benefits of dietary restriction may not stem solely from calorie reduction but also from the moderation of protein intake. Limiting protein to recommended levels (0.8 grams a day per healthy kilogram of body weight, or approximately 0.4 grams per pound) could be more efficient than overall dietary restriction—it suppresses TOR and IGF-1 (Insulin-like Growth Factor, a hormone that manages the effects of growth hormone in the body), the two pathways believed to be responsible for the health and longevity benefits. Understanding the role of specific proteins in our diet empowers us to make informed choices. The amino acid leucine stands out for its significant effect on TOR. Reducing leucine intake may be almost as effective as lowering overall protein consumption. This knowledge allows us to make conscious decisions about our diet, as leucine is predominantly found in animal products—eggs, dairy, and meat, including chicken and fish—while plant foods like fruits, vegetables, and legumes contain much less.

Okinawans have historically been one of the longest-living populations; they provide an inspiring example of the potential of a balanced, mostly plant-based diet for longevity, consisting predominantly of legumes, rice, and tofu. Sweet potatoes alone constituted 67% of their diet. They only consumed fish in small amounts, with meat, eggs, and dairy products, each contributing less than 2 percent to their diet. Their diet is known only to contain an estimated 1.1g of sodium. Okinawans also apply the “stop eating when 80% full” philosophy, often recited as a mantra before a meal, naturally reducing food consumption. (Live to a 100 Secrets of the Blue Zones; Netflix documentary series episode 1) The series also analyses the Sardinian population, which contains many centenarians following a traditional Mediterranean diet. So, the principle is not just about eliminating animal protein but focusing on predominantly consuming a low Glycemic Index (GI), complex carbohydrates, and high fiber diet. (see our blog series Complex versus Simple or processed Carboydrites) A balanced diet rich in fruits, vegetables, whole grains, seeds, nuts, olive oil, and moderate lean meat proteins. This diet contains high levels of antioxidants and anti-inflammatory compounds, contributing to its protective effects against aging and disease. (Sardinia, episode 3)

The Okinawans and Sardinians have some interesting commonalities. In principle, as rural communities, they kept out the corrosive forces of modernization: They have kept a diet unchanged for hundreds of years. They are naturally/functionally active and value high community engagement.

The Slender Solutions Team