In 1935, Clive McCay, a researcher from Cornell University, published a study in the Journal of Nutrition. His research revealed that the restriction of calories without malnutrition prolonged the lives of rats 33% longer when compared to rats that were fed the average diet. Since this groundbreaking research was published, countless studies have demonstrated the impact that calorie restriction has on lifespan, with many of these studies showing that calorie restriction can extend lifespan from 50 to even 300%.
Now, while many of these studies were either animal-based or featured non-human participants, they have been peer-reviewed and published by reputable sources. As such, calorie restriction could have important implications for human longevity.
What exactly is calorie restriction?
As the name suggests, calorie restriction is about cutting back on your calorie intake, without intentionally causing malnutrition or depriving oneself of essential nutrients. The idea is that restricting one’s intake of calories will trigger metabolic changes that will benefit one’s health.
How does calorie restriction help longevity?
1. Anti-aging effects on the cells
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Ideally, aged and damaged cells are removed from the body via the immune system. Unfortunately, like many things, aging affects the functionality of the immune system, making it harder for it to carry out this very important job.
Before long, these aged cells accumulate, leading to a weaker immune system and health system.
As a result, it is important to find ways to not only mitigate accelerated cell aging, but to also adequately address the already existing aged (senescent) cells. According to research, calorie restriction has been found to prevent the accumulation of aged cells.
Additionally, calorie restriction has also been found to regulate autophagy, which is a process whereby old cells are broken down and essentially recycled for other vital cellular functions.
2. Improves cardiovascular health
With heart disease being the leading cause of death worldwide, adopting measures that assist in promoting cardiovascular health is of utmost importance. One of these measures seems to be calorie restriction, as research has found that it may reduce risk factors associated with heart disease.
A review article published in Nature referenced studies that showed how calorie restriction reduced blood pressure and improved heart function.
3. Improves cognitive function
With 150 million people set to be living with Alzheimer’s by 2050, it is now more important than ever to find ways to protect brain health and function.
According to one study, calorie restriction may help you do just that. The study, published in PNAS, found a strong association between individuals who followed a calorie-restrictive diet and increased verbal memory scores.
4. Boosts longevity
As stated, the interest in calorie restriction stems from its ability to boost lifespan in animals, which can then hopefully be translated to human studies.
Last year, a Yale study found that individuals who adopted moderate calorie restriction experienced a reduction in the production of the protein SPARC, which then prevents harmful inflammation and encourages healthy aging.
A separate study, focused on rats, found that after putting them on a calorie-restricted diet, the rats experienced anti-aging effects, such as protection against cellular aging and the reversal of age-related immune dysfunction.
“The effect of caloric restriction on extending healthspan and lifespan suggests that aging is reversible and druggable. We hope that we can identify the intervention target to mimic the beneficial effect of caloric restriction in the future.” – says Guang-Hui Liu, study co-author and professor at the Chinese Academy of Sciences
Following a calorie-restricted diet
As opposed to just cutting back on calories, the calorie-restricted diet emphasizes the consumption of essential nutrients while you cut back your calorie intake by 20 to 40%.
Processed foods and fast foods are typically high in calories, but absolutely void of nutrition, whereas vegetables, fruits, whole grains, and legumes are typically low in calories but rich in essential nutrients. If you are going to adopt this eating pattern, make sure to ask your healthcare provider for their opinion first.
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Can calorie restriction be harmful?
In 1950, researchers had participants reduce their calorie intake by 40% in order to mimic the dietary conditions during World War II.
According to the findings, the side effects of the study included severe periods of emotional distress, depression, suicidal thoughts, reduction in sex drive, and poor cognitive function.
It’s clear that without getting the necessary nutrients, reducing your calorie intake can have serious consequences for your health. In fact, research has found that excessive calorie restriction may cause the following issues:
- Low nutritional intake, which causes nutritional deficiencies like fatigue and anemia
- menstrual irregularities, which increases infertility risk
- Lower bone density, which increases the risk of osteoporosis
- Depression and anxiety
- Low blood sugar (hypoglycemia)
What are the alternatives to calorie restriction
Adopting a long-term approach to calorie restriction may not always be a safe option, which is why researchers are finding alternatives that can mimic the beneficial effects of calorie restriction.
One alternative that’s been identified as a calorie restriction mimetic is resveratrol. As of 2003, there has been great interest in this compound and its effects on longevity. In fact, one study noted that resveratrol mimics the effects of calorie restriction, protecting against chronic diseases like diabetes and heart disease.
Another popular calorie restriction mimetic is the anti-diabetic drug metformin. According to a 2022 study, metformin was found to have caloric restriction-related longevity benefits.
Spermidine is another anti-aging compound that has been identified as a calorie restriction mimetic, and it’s been found to provide many health benefits for the body.
Takeaway
There are numerous studies that have exhibited the benefits of calorie restriction, unfortunately, the participants of these studies are rarely human, and when they are, further research is still needed to confirm the studies’ findings.
With the world’s aging population numbers on a steady rise, it is important to find ways in which we can promote healthy living and protect health span. Now, while further research is needed to better determine just how calorie restriction can support lifespan, it may be exactly what we need to do should we want to support our longevity.
