People around the world are becoming increasingly interested in healthy aging. Many hope not only to live longer but also to remain physically active, mentally sharp, and independent as they grow older.
Because of this, anti-aging advice has become extremely popular online.
Some people spend money on expensive supplements, cold-water therapy, red-light devices, or oxygen treatments in hopes of improving lifespan. However, scientists say one of the most effective methods may actually be much simpler and far less expensive: eating slightly fewer calories.
Researchers from Tufts University and other major research centers have reported that modest calorie restriction may improve health and reduce risk factors linked to aging-related diseases.
Their findings come from a long-running research project known as CALERIE, which stands for Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy. The study has followed participants for many years and continues to produce new scientific findings.
The research was published in The American Journal of Clinical Nutrition.
Scientists involved in the study say one of the most surprising findings is that people do not need dramatic calorie cuts to gain benefits. Even reducing food intake by around 10% to 15% may improve important measures of cardiovascular and metabolic health.
The idea behind calorie restriction is not new. Earlier animal studies suggested that eating less while still maintaining good nutrition could help extend lifespan and reduce age-related disease. However, proving similar effects in humans has always been much more difficult.
The CALERIE project became one of the first major attempts to carefully study long-term calorie restriction in healthy human adults.
In the original phase of the study, researchers recruited healthy adults without obesity. The participants were divided into two groups. One group attempted to reduce calorie intake by 25% for two years, while the other group continued their usual eating habits.
The participants regularly visited research centers at Tufts University, Washington University, and Louisiana State University for detailed testing. Scientists measured blood pressure, body weight, cholesterol, insulin levels, glucose tolerance, and many other health indicators.
Researchers say the participants showed impressive commitment because the study required major lifestyle adjustments and long-term follow-up.
In reality, most participants did not achieve the full 25% calorie reduction researchers originally planned. Instead, participants lowered their intake by an average of around 12%.
Even so, the results were surprisingly strong.
Compared with the control group, participants who reduced calories showed lower blood pressure, lower LDL cholesterol, improved insulin sensitivity, and healthier glucose metabolism.
Although weight loss was not the primary goal, participants still lost around 10% of their body weight on average.
Scientists say these changes are important because they affect many diseases linked to aging, including heart disease, diabetes, and metabolic disorders.
The researchers also found that participants gradually changed the types of foods they ate. Many consumed less fat and more protein and carbohydrates during the study.
Importantly, newer analysis published in 2026 found that calorie restriction did not appear to damage the nutritional quality of participants’ diets.
Participants received multivitamins and calcium supplements during the trial, but researchers later concluded that many participants still maintained adequate nutrition through food alone.
Scientists are still investigating why eating less may improve health. One possible explanation involves oxidative stress.
When the body converts food into energy, it naturally produces unstable molecules called reactive oxygen species. These molecules can damage cells over time and may contribute to aging and diseases such as cancer, heart disease, and neurodegenerative disorders.
Urine testing during the study showed lower levels of reactive oxygen species in the calorie restriction group compared with participants eating normally.
This suggests the body may function more efficiently under moderate calorie restriction, producing less harmful cellular damage.
The researchers have continued following participants long after the original study ended. They recently invited volunteers back for additional testing to see whether earlier calorie restriction still influences health more than a decade later.
Scientists also want to know whether participants continued restricting calories on their own after the study ended.
The researchers believe these long-term findings may become increasingly important as medical advances allow people to live longer. Extending lifespan alone may not be enough if those additional years are spent dealing with serious chronic disease or disability.
The scientists also stress that calorie restriction is not appropriate for everyone. Older adults over 65, children, pregnant individuals, people with low body weight, those with bone loss, and individuals with certain medical conditions should seek medical advice before changing calorie intake.
For healthy adults, however, modest reductions may be relatively easy to begin.
Researchers suggest people first estimate their usual daily calorie intake using online calculators. A 10% reduction may be enough to produce benefits for many people.
For example, someone consuming 2,000 calories daily might only need to remove one dessert, sugary coffee drink, or unhealthy snack from their routine.
Some individuals may prefer intermittent fasting approaches, such as the 5:2 method, where calorie intake is restricted only on certain days of the week.
Scientists emphasize that there is no need for extreme dieting. The study suggests moderate, sustainable calorie reduction may already provide meaningful health improvements.
The researchers also advise listening carefully to the body. Feeling weak, dizzy, exhausted, or becoming underweight may signal that calorie restriction has become unhealthy.
If you care about weight loss, please read studies that hop extract could reduce belly fat in overweight people, and early time-restricted eating could help lose weight .
For more health information, please see recent studies about a simple path to weight loss, and results showing a non-invasive treatment for obesity and diabetes.
The findings were published in The American Journal of Clinical Nutrition.
Source: Tufts University.
