Reducing calories can have health benefits, even if you don’t need to lose weight. In a two-year study, non-obese participants who cut 300 calories from their diets reduced their cholesterol levels, blood pressure, inflammation and other key health markers.
Mountains of evidence show that obese people stand to gain from eating less and losing weight. Now, a study suggests that even healthy, non-obese people can lower their risk of chronic diseases, including type 2 diabetes and heart disease, simply by cutting 300 calories a day.
The two-year study, published in July 2019 in the journal The Lancet Diabetes & Endocrinology, found that people under 50 who were normal weight or overweight, and had healthy levels of cholesterol, blood pressure blood pressure and blood sugar could be healthier with moderate calorie reduction. Basically, six cookies, 30 chips, or a 2/3 cup serving of vanilla ice cream is just over 300 calories, depending on the product.
Study participants lost an average of 5kg over the course of the study, but detailed analysis revealed that only about 25% of the benefits were directly related to weight loss, says the study’s lead author . These results suggest that there is something about calorie restriction itself that improves health. The results are important because this is the first long-term calorie restriction intervention in healthy non-obese people that demonstrates that modest calorie restriction significantly improves cardiometabolic risk factors.
Could eating less be the best medicine?
The researchers randomly assigned the participants to either the calorie restriction group or a control group that had no restrictions on their food intake. The calorie restriction group consisted of 143 people (44 men and 99 women), while the control group consisted of 75 people (22 men and 53 women). The study population was 76% white, 15% African American, and 9% Asian, Native American, or Pacific Islander, with an average age of 38 years. The participants’ average baseline body mass index (BMI) was 25.1, which puts them in the normal-to-overweight range.
The researchers chose a younger, mostly normal-weight population for a few key reasons. The researchers designed this study based on results already seen in animal trials where calories were restricted. In most cases, the earlier caloric restriction begins, the greater its effects on lifespan and healthy life expectancy. Healthy life expectancy is the period between the start of the intervention and the onset of the disease. The researchers wanted to see what benefits, if any, calorie restriction might have for people who are not overweight.
During the first month of the study, the subjects ate three meals a day designed to reduce their daily calorie intake by 25% and familiarize them with their new normal. After a month, participants were able to choose from a variety of food plans that the researchers modified to suit different cultural preferences. In addition to receiving training in the basics of calorie restriction, participants attended group and individual counseling sessions during the first six months of the trial.
Maintaining a 25% calorie reduction proved difficult despite the support received by the participants. The majority of them did not reach the set goal, since they only reduced, on average, 12% of their calories at the end of the trial.
Although they did not reach the goal set by the researchers, participants in the restriction group tended to eat less fat than the control group. At the same time, they recorded a large increase in their intakes of vitamin K and magnesium, which are markers of a generally healthy diet, including foods such as green vegetables, whole grains and legumes,” as beans, lentils, edamame and chickpeas.
Impressive health benefits
After two years, the calorie-restricted group saw many health improvements, including:
A significant decrease in total cholesterol and LDL, the “bad” cholesterol.
a 24% drop in serum triglyceride levels, a type of fat in the blood, as well as improved insulin sensitivity (which reduces the risk of type 2 diabetes)
a significant reduction in systolic, diastolic, and mean blood pressure (although baseline blood pressure values were normal for participants at the start of the trial)
A significant reduction in the metabolic syndrome score, which takes into account waist circumference, systolic blood pressure, HDL (the “good” cholesterol) levels, triglycerides and blood sugar to determine certain risks, such as heart disease.
a reduction in a biomarker that indicates chronic inflammation and has been linked to heart disease, cancer and cognitive decline.
These results show that altering calorie intake could reduce the burden of diabetes and cardiovascular disease that we have in this country. It would be difficult to find a drug combination that would achieve the kind of reductions achieved in the calorie restriction group. Although participants who reduced their calorie intake lost about 10% of their body weight, this is not the determining factor in these results. There’s something about calorie restriction, a mechanism that researchers don’t yet understand, that drives these improvements.
Calorie restriction: The new fountain of youth?
There could also be implications for what caloric restriction interventions might do for long-term health, even for people who try it for a set period of time rather than for life.
Although it has not been proven or is not part of this study, researchers believe that calorie restriction, even in young people of normal weight, could help “reset the baseline”, i.e. that is, to delay the time it takes for people to develop potentially serious illnesses. The next steps in research would be to combine calorie restriction with other lifestyle interventions, such as modest physical activity, and track the changes. It would be interesting to compare the continuous calorie restriction used in this study with other methods, such as intermittent fasting, to see how it might improve cardiometabolic risk factors.
A Simple Way to Try Limiting Calories
Reducing 300 calories a day may seem daunting, but calorie counting isn’t necessary. The easiest way to do this is to not eat after dinner. This is where most of the unnecessary calories come from and this is where you can make an impact without too much pain.
