What would you be willing to give up if you could maintain good health as you age? Money? Your car? Would you exercise more? Most of us probably would. But would you willingly give up 30-60% of your calories?
Researchers have been studying caloric restriction, and while most of the studies have taken place on animals, the results show that reducing how much you eat might be one of the only ways to maintain your health as you age. Obviously, this discovery is incredibly exciting. And a big reason why so many people have taken to calorie restriction diets today. It seems that the craze is everywhere. But let’s dig a little deeper.
What is caloric restriction?
Daily recommended calorie intake will vary from person to person depending on several factors including age, gender, and lifestyle. But it’s usually recommended that men eat somewhere in the 2,500 calorie range while women should eat roughly 2,000 calories.
Calorie restriction means reducing this number of calories throughout the day by 30-60% but without treading into the territory of malnutrition. Because of the risk of malnutrition is so high, it is recommended to do these diets under medical supervision.
Let’s take a moment and be really clear here. Do not confuse this with fasting or intermittent fasting diets. Those differ fundamentally in that they simply cut out all food, either during the entire day (fasting) or during a set period of time during the day (intermittent fasting). A calorie restriction diet makes your meals child size in an effort to cut down the calories you typically consume.
For many, a 30-60% reduction in calories sounds like the stuff of nightmares (if you’re one of these people, we don’t blame you). Others might be padlocking their refrigerators to cut down on their intake right now. No matter which side of the fence you’re on however, it’s interesting to look at what the science says about calorie restriction and the potential role it plays in longevity.
Caloric restriction and lifespan in animals
The science behind caloric restriction goes all the way back to 1930 when Cornell scientist Clive McKay unexpectedly discovered that rats on a calorie restricted diet experienced more health benefits than rats eating their normal intake of food.
Since then, the scientific community has expanded its investigation. Researchers have found that this type of diet significantly impacts the biology of yeast, worms, flies ,and mice. In another study, scientists found that monkeys who consumed 30% fewer calories experienced more benefits than those on a regular diet. In fact, six of the 20 monkeys on a calorie restricted diet were able to increase their average lifespan.
But hold on. Before you start throwing half your food down the garbage disposal, let’s pump the brakes for a second. While these studies might be promising, the results are inconclusive and varied. While one study on monkeys, for example, showed an increased lifespan, another did not. It’s important to remember that when it comes to caloric restriction – and especially caloric restriction in humans – science is still in its infancy. What’s important is the potential these studies are revealing. They’re showing how a physiological input can potentially unlock the body’s own biology to support healthy aging.
Sirtuins and their role in calorie restriction
The recent studies we just discussed have prompted several people to cut a (not-insignificant) percentage of the recommended calories from their daily diets. And their new regimen had some interesting effects. In the second year of the study, participants showed a dramatic drop in their night time metabolic rates, as well as a small (but significant) drop in their body temperature as they slept. This lower metabolic rate might be the body’s attempt to conserve energy when food is scarce.
Interestingly, participants also experienced a 20% drop in cellular oxidative stress and decreased cellular damage–two things linked to the normal aging process.
As science has tried to further understand how calorie restriction was leading to such a wide range of health benefits, they found something rather interesting. In calorie restricted organisms, the activity of recently discovered proteins called “sirtuins” had significantly increased. Furthermore, when the sirtuins were removed from the equation, caloric restriction no longer had the same effects on normal longevity and health. So sirtuins were the key.
This led to a flurry of research on these mysterious proteins. And in the years since, scientists have discovered they play a significant role in a myriad of health benefits. Everything from vascular and joint health to mood and motivation.
The health benefits behind caloric restriction
So does eating less really add up? Probably yes. And often the benefits behind a calorie restriction diet extend well beyond the potential impact on healthy aging, impacting our daily lives for the better.
According to Mark Mattson, PhD, chief of the Laboratory of Neurosciences at the National Institute on Aging, “There seem to be two mechanisms by which a restricted-calorie diet supports healthy longevity. First, it reduces free radical production, highly damaging molecules that can damage cellular structures. The second is that calorie restriction increases the resistance of cells to stress. Both of these are important in protecting against negative impacts on the normal aging process. Here are some of the benefits that come with cutting down on the calories.
Caloric restriction increases energy efficiency
In a recent study, 12 healthy male athletes restricted their caloric intake by 33%. Among the findings was greater energy efficiency. This is largely due to the positive affect caloric restriction has on mitochondrial activity. Caloric restriction, according to the study, induces mitochondrial biogenesis and bioenergetic efficiency, reduces mitochondrial oxygen consumption and increases membrane potential, and generates less reactive oxygen species, all being able to maintain their critical ATP production.
Caloric restriction maintains heart health
Research by the National Institute on Aging showed that even a slight reduction in caloric intake provided significant cardiovascular benefits. Specifically, adults who restricted their calories by 12% — about 300 fewer calories a day — saw significant improvement in metabolic syndrome score compared with adults on a control diet after 12 months. Some of these benefits went well beyond weight loss too, including
lower helping to maintain healthy cholesterol levels already in a normal range.
Should you try a caloric restricted diet?
If you’re considering starting a caloric restricted diet, there are several important factors you should keep in mind. First off, remember that the human-based science powering these diets is still relatively new. As such, you should consult your doctor or dietician before beginning.
Secondly, and often the most overlooked part of a caloric-restricted diet is remembering that arbitrarily slashing your calorie count isn’t the goal. If you’re counting your calories, the goal should always be to make every calorie count. This means ensuring that you’re getting the proper amount of nutrients in your diet. It is easy to venture into the territory of malnutrition or nutrient deficiency, therefore caloric restriction should only be done under the supervision of a medical professional.
If you want to just dip your toe into calorie restriction, don’t make sudden, dramatic changes in your diet. Instead, consider starting slowly by eliminating refined sugars and replacing them with healthier options.
While caloric restriction is still relatively new, we’re excited for its potential positive impact on biohacking and healthy aging. With the right amount of research, caloric restriction could end up being a valuable tool in every biohacker’s belt.