Can Restricting Calories Extend Your Healthy Lifespan?

Calorie restriction and fasting have emerged as popular health practices in recent years. Calorie restriction is the reduction of one’s daily caloric intake to levels that are below average or habit.  It involves eating less throughout the day or fasting for certain meals.  This practice is accomplished while also ensuring that nutrient needs are met.

Calorie restriction has several benefits and drawbacks.  Scientific American cites a study by the University of Wisconsin-Madison and the National Institute on Aging in which rhesus monkeys greatly benefitted from chronic calorie restriction diets. These primates have similar aging patterns to humans, and when a 16-year old rhesus monkey’s diet was reduced by 30%, it lived to be over 40 years old, breaking the lifespan record for rhesus monkeys who usually only live to be around 25 years old.  Researchers concluded that the effects of calorie restriction on primates are similar to humans in increasing longevity. 

Another study indicated that practicing a fasting-like diet for 5 days a month in 3-month intervals can reduce the risk of age-related illnesses in humans. The benefits of this diet persisted for at least 3 months after the study participants returned to their regular diet.

However, while calorie restriction has its benefits, some studies show that it can be ineffective.  Some researchers claim pharmaceutical options have more effective outcomes, while others believe simply eating right and exercising is the best practice in maintaining a healthy weight and avoiding the risk of age-related illnesses.   

Furthermore, other health researchers question the line between calorie restriction and anorexia.  Can calorie restriction become an eating disorder?  How can we distinguish the two?  A Slate article titled “Calorie Restriction, the Newest Eating Disorder,” proposed psychological similarities of both the sufferers of anorexia and those who practice chronic fasting.  The article suggests that both groups seek a “sense of purpose” or control in restrictive eating.  

The Science

So how much would you need to restrict your calories to experience a longevity benefit?  According to a University of Southern California study conducted by Valter Longo, simply restricting your food intake for 5 days in a row in a month for 3 months straight (and repeated as needed), can reduce your risks for aging and age-related illnesses.  Test subjects who maintained this regimen (around 1,100-calorie diet for the first day and 700-calorie diet for the following four days) saw weight loss and better triglyceride, glucose, and cholesterol levels after just three months.  Longo notes that the regimen had a 25 percent dropout rate because of difficulty, and it was most effective on people who were obese or unhealthy.   

What Mechanism in the Body Causes these Anti-Aging Benefits?  

Research published in the Proceedings of the National Academy of Sciences and carried out by a team under Joshua Sanes and Jeff Lichtman suggests that calorie restriction and exercise reduced the symptoms of aging by revitalizing connections between nerves and muscles.  In other words, these practices “act...by attenuating or reversing the decline in our synapses”.  This mechanism directly leads to the health benefits experienced by those in Longo’s study. 

Additionally, according to Mark Mattson, Ph.D., chief of the Laboratory of Neurosciences at the Institute on Aging, calorie restriction “reduces free radical production, or the production of highly damaging forms of oxygen” (source) and greatly increases the ability of cells to resist stress. 

Finally, it’s important to note that most calorie restriction practitioners frequently exercise, and these two lifestyle factors paired together produce these results.

Vitamins and Supplements 

According to the Calorie Restriction Society, an organization whose goal is to help people live longer lives while eating fewer calories and maintaining adequate nutrition, it’s possible to restrict your calorie intake while consuming enough vitamins and nutrients.   

For people who follow calorie restriction, food consumption is a lot more nutrient dense than average.  For example, these diets are often rich with fruits, vegetables, nuts, and olive oils and lack empty calorie foods like pizza.  Eating nutrient-dense foods ensures that you are meeting your vitamin and mineral level needs while also eating fewer calories.  Foods high in healthy fats can be the most challenging for practitioners of calorie restriction to incorporate into their diets because those foods are typically also high in calories. 

However, most people lead busy lives and find it difficult to plan and cook nutrient-dense meals.  To ensure that practitioners of chronic calorie restriction consume adequate levels of vitamins and minerals, some health researchers have recommended taking supplements.  This practice will decrease the likelihood of malnutrition on a low-calorie diet. (source) 

Resources

There are many resources available for those who wish to pursue calorie restriction to increase longevity.  Here is a list of websites that provide information on longevity research, vitamin maximization, and firsthand accounts from calorie restriction practitioners.

Calorie Restriction Society: This website contains forums and resources that cover meal prep, meetups for the calorie restriction community, and research on longevity and the health benefits of calorie restriction. 

The CR Way: Using the Secrets of Calorie Restriction for a Longer, Healthier Life: Written by Paul McGlothin, Vice President for Research and Director of the Calorie Restriction Society, and Meredith Averill who serves on its Board of Directors.  The book combines longevity research with best practice methods for a calorie restriction diet.

Beyond the 120 Year Diet : How to Double Your Vital Years: Written by Roy Walford, M.D., a pioneering researcher in the anti-aging field, explains the basics of the calorie restriction diet and includes research on longevity and aging.

Cronometer: Cronometer is a free online fitness tracker dedicated to practitioners of calorie restriction.  Users can log their diet, exercise, biometrics, and fitness notes.