The benefits of following a healthy diet when it comes to preventing poor cardiovascular outcomes may vary depending on your body weight — with obese people getting less of a benefit — according to a new study published in the American Journal of Preventive Cardiology.
Researchers have long known that the quality of a person’s diet affects their risk for cardiovascular disease, in part because a healthier diet is linked to a lower body-mass index (BMI, a measure of body weight that takes height into account). But there hasn’t been much research on how the quality of a person’s diet affects their risk for cardiovascular disease once you take body weight out of the equation — that is, by comparing diet quality with cardiovascular outcomes among people in the same category of body weight. For the latest study, researchers set out to do just that, using data from six different groups of participants who took part in research studies in the United States.
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Overall, there were 30,219 participants in the study, and each participant had their diet — which they reported in answers to survey questions — evaluated using a scoring system called the alternative Healthy Eating Index-2010 (aHEI-2010). Based on their score, participants were then divided into five groups of equal size. The researchers looked at the number of cardiovascular events in each group — a combined count of strokes, heart attacks, new cases of heart failure or coronary artery disease (CAD), and death from cardiovascular causes. In this comparison between groups, the researchers looked separately at the results among participants with a BMI of 18.5-24.9 (normal or healthy weight), 25.0-29.9 (overweight), and 30 or higher (obese).
Healthy diet without weight loss not linked to reduced heart risk in obese participants
During a median follow-up period of 16.2 years, there were 7,021 cardiovascular events among all participants. After adjusting for factors other than diet that are known to affect a person’s risk for cardiovascular disease, the researchers found that among participants with a normal body weight, the group with the highest healthy diet score experienced 43% fewer cardiovascular events than the group with the lowest score. Among overweight participants, the group with the highest healthy diet score experienced 31% fewer cardiovascular events than the group with the lowest score. But among obese participants, the group with the highest healthy diet score experienced only 3% fewer cardiovascular events than the group with the lowest score — not a statistically significant difference, meaning it was small enough that it could have been due to chance alone.
The researchers concluded that following a healthy diet was linked to a lower risk for cardiovascular events in normal-weight and overweight U.S. adults, but not in obese adults. Since obesity is a well-known risk factor for cardiovascular disease and cardiovascular events, these results underscore how important it is for people with obesity — and their health care providers — to explore healthy weight-loss options, rather than focusing just on following a healthy diet that may not lead to significant weight loss.
Want to learn more about protecting your heart? Read “Be Heart Smart: Know Your Numbers,” “Does Diabetes Hurt Your Heart?” “Fight Off Heart Disease With These Five Heart-Healthy Foods” and “Lower Your Risk of Heart Disease.”