One of the best ways to live a long and healthy life is to reduce your risk of developing chronic health conditions, such as cancer, diabetes, and heart disease. Emerging evidence shows that caloric restriction may help prolong health span and lifespan, but how does it work? Before diving into these topics, let’s start off by defining what calorie restriction is.
What is calorie restriction?
Calorie restriction involves reducing your dietary intake to less than what you would normally (or habitually) consume while still maintaining adequate intake of all essential macro and micronutrients. The number of calories restricted varies depending on the protocol, however, it usually means slashing your daily intake by 10% of your daily needs or more. Calorie restriction has consistently been shown to assist with weight loss, however, more extreme programs (such as eating less than 800 calories/day) can result in serious health issues [13
]. Intermittent fasting, low carb diets, ProlonFMD, keto, Nutrisystem, and other diets incorporate calorie restriction in some form.
Benefits of caloric restriction
A growing body of evidence suggests that calorie restriction offers health benefits beyond weight loss. Let’s discuss how this can increase longevity, as well as fight against chronic health diseases.
Most studies on calorie-restricted diets and aging have been conducted on animals and many have shown that calorie restriction extends the lifespan and reduces risk of chronic disease. Recently, a clinical trial at Duke University called CALERIE (Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy) demonstrated that reduced calorie intake has the potential to increase longevity by improving a wide variety of biomarkers that reduce the risk for chronic disease. Increasingly, it appears that calorie restriction helps renew cells and boosts mitochondrial function, both of which underpin the aging process [14
Calorie restricted diets have been shown to have a positive impact on various markers of metabolic health including waist circumference, blood LDL cholesterol, triglycerides, insulin resistance, metabolic syndrome risk, HDL cholesterol and glucose control [1
]. These biomarkers are predictors of overall health and help determine your risk of developing serious health conditions, such as cardiovascular disease, cancer, stroke, diabetes, and Alzheimer’s.
Learn more about how to reduce LDL cholesterol without medication here
Cardiovascular disease (CVD) is the leading cause of death worldwide, and largely impacted by diet. Studies on rhesus monkeys found that calorie restriction reduced the incidence of CVD by 50%, and human studies show that calorie-restricted diets improve risk factors for heart disease, including LDL and HDL cholesterol, blood pressure, and heart rate variability
. Results from the CALERIE study demonstrated that two years of moderate calorie restriction induced several positive cardiometabolic adaptations [1
Cancer is another top killer worldwide, and caloric restriction shows promise for both cancer prevention and treatment. Calorie restriction improves metabolic and hormonal factors associated with cancer risk, such as insulin sensitivity, blood glucose, growth factor signaling and inflammation [1
With regards to cancer treatment, studies have shown that energy restriction can enhance the efficacy of chemotherapy and reduce associated symptoms in some cases [3
]. However, there are some concerns regarding the use of calorie restriction in cancer patients due to their increased risk of weight loss, cachexia, and sarcopenia, and this should only be undertaken under medical supervision [3
Stroke is the fifth leading cause of death and occurs when there is reduced blood supply to the brain, usually due to a blood clot or blood vessel rupture [4
]. High blood pressure and high LDL cholesterol are risk factors for having a stroke, both of which are reduced in calorie restriction [1
Type 2 diabetes is another leading cause of death in the United States and insulin resistance is a hallmark of the disease. The CALERIE study demonstrated that calorie restriction significantly improved insulin sensitivity and reduced plasma fasting glucose, putting individuals at a decreased risk for diabetes [1
]. Recent studies indicate that calorie restriction is also helpful for managing type 2 diabetes by aiding in weight loss and restoring normal glucose levels, eventually leading to remission of the disease [5
Alzheimer's is a neurodegenerative disease associated with aging that results in memory loss and decline in cognitive function. Animal studies have shown that calorie restriction can help delay the onset and progression of neurodegenerative diseases (such as Alzheimer’s). Moreover, recent human clinical trials demonstrate that calorie restriction is associated with cognitive improvement [6
There is not yet enough evidence to conclude that calorie restriction reduces all-cause mortality in humans. However, a 20-year longitudinal study on rhesus monkeys showed that caloric restriction reduces both age-related and all-cause mortality, a finding that may also have implications for humans in the years to come [7
Problems with calorie restriction
Although evidence suggests that calorie restriction has the potential to increase lifespan and reduce risk of chronic disease, it does come with some caveats. Calorie restricted diets may not be sustainable and can be dangerous for those with certain medical conditions and/or a history of eating disorders.
Furthermore, extreme calorie restriction can lead to malnutrition, low bone density, reduced physical performance, and impaired cognitive ability [8
]. If you choose to follow a calorie restricted diet, it should be done carefully, to ensure adequate nutrient intake.
Calorie restriction is a dietary approach to increase longevity and decrease the risk of developing chronic health conditions including cardiovascular disease, cancer, stroke, diabetes, and Alzheimer’s. Studies on both animal and human subjects indicate that calorie restriction without malnutrition has the capacity to improve health and extend life. However, calorie-restricted diets may be difficult to stick to and aren't appropriate for all individuals.
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