Many people search for complicated ways to slow aging and stay healthy longer. Social media and the internet are full of advice about cold plunges, expensive supplements, oxygen therapy, fasting plans, and special anti-aging routines.
But scientists say one of the most effective methods may actually be surprisingly simple: eating a little less food each day.
Researchers from Tufts University and other institutions have found that modest calorie reduction may improve long-term health and lower the risk of many age-related diseases. Importantly, the benefits appeared even when people reduced their calorie intake by only a small amount rather than following an extreme diet.
The findings come from a long-running scientific project called CALERIE, which stands for Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy. The study has been running for nearly two decades and continues to provide new insights into how eating habits affect aging and health.
The work was published in The American Journal of Clinical Nutrition.
Scientists involved in the research say the study shows that people do not need to follow severe starvation diets to gain benefits. Even reducing daily calories by around 10% to 15% may improve several important markers linked to aging and disease.
Sai Krupa Das, a senior scientist at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, explained that simple nutrition and lifestyle changes may not only prevent disease but may also slow the biological aging process.
The CALERIE study originally began many years ago and included healthy adults without obesity. Researchers wanted to test whether long-term calorie restriction could safely improve health in humans, similar to findings from animal studies.
During the first phase of the study, 143 participants attempted to reduce their calorie intake by 25% for two years. Another 75 participants continued eating normally and served as the comparison group.
Participants regularly visited one of three research centers involved in the study, including Tufts University, Washington University, and Louisiana State University. Scientists carefully measured many aspects of health, including body weight, blood pressure, cholesterol, insulin levels, and glucose tolerance.
Researchers say the participants showed remarkable dedication because they agreed to follow the study even without knowing whether they would be placed in the calorie restriction group or the normal eating group.
Although the researchers originally hoped participants would reduce calories by 25%, most people only achieved an average reduction of about 12%. Even so, the health improvements were impressive.
Participants who reduced calories showed lower blood pressure, lower LDL cholesterol, improved insulin levels, and better glucose control compared with people who continued eating normally.
Interestingly, weight loss was not the main goal of the study, but participants still lost around 10% of their body weight on average.
Scientists say one of the most important findings is that moderate calorie reduction appeared realistic and manageable for many people. The benefits were seen without extreme dieting, suggesting that healthier aging may be possible through relatively small changes in eating habits.
Researchers also noticed that participants naturally shifted their eating patterns during the study. Many reduced their intake of fats and increased protein and carbohydrate intake instead.
Another important finding from more recent research was that reducing calories did not appear to harm the nutritional quality of participants’ diets.
Participants were given multivitamins and calcium supplements during the study as a precaution, but later analysis suggested most participants still consumed adequate nutrition even without those supplements.
Scientists are still trying to fully understand why calorie restriction improves health. One theory involves molecules called reactive oxygen species. These unstable molecules can damage cells and contribute to aging and diseases such as cancer, heart disease, and Parkinson’s disease.
The researchers found that participants who restricted calories had lower levels of reactive oxygen species compared with the control group. This suggests the body may process food more efficiently when calorie intake is lower, producing less harmful cellular stress.
The CALERIE project is still continuing today. Researchers recently invited participants back for long-term follow-up testing to see whether the earlier lifestyle changes are still affecting their health more than a decade later.
Scientists also want to learn whether participants continued restricting calories after the original study ended and whether long-term moderate calorie reduction produces lasting health benefits.
The researchers believe these long-term findings could become especially important as modern medicine helps people live longer lives. Living longer may not necessarily improve quality of life unless those additional years are spent in relatively good health.
Although moderate calorie restriction may benefit many adults, the researchers also caution that it is not suitable for everyone.
Older adults over age 65, young children, pregnant people, individuals with very low body weight, people with bone density problems, and those with certain medical conditions should speak with a doctor before reducing calorie intake.
For healthy adults, however, getting started may be easier than many people think. Researchers suggest using online tools to estimate current calorie intake and then reducing that amount slightly.
For someone eating around 2,000 calories daily, a 10% reduction could simply mean removing one sugary coffee drink or skipping a dessert each day.
Some people may prefer approaches such as intermittent fasting, where calorie reduction happens only on certain days of the week. Researchers say different methods may work for different individuals.
Scientists also emphasize that people should pay attention to how their body feels. If someone becomes underweight, constantly tired, dizzy, or weak, the calorie reduction may be too aggressive.
Importantly, the researchers stress that extreme calorie restriction is not necessary. Even relatively small changes may produce meaningful health improvements over time.
After reviewing the findings, the study appears important because it provides long-term human evidence that moderate calorie reduction may improve several major markers linked to aging and chronic disease. The improvements in blood pressure, cholesterol, insulin levels, and oxidative stress are especially encouraging.
Another strength is that the calorie reduction achieved by participants was moderate and realistic rather than extreme. However, researchers still need more long-term data to understand whether the benefits continue over many decades and whether calorie restriction affects lifespan directly.
Overall, the findings suggest that modest reductions in calorie intake may be one practical strategy for supporting healthier aging.
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The findings were published in The American Journal of Clinical Nutrition.
Source: Tufts University.
