Low-Carb Vs Low-Fat Diet: Here's What Actually Protects Your Heart, Reveals Study

Diet plays a crucial role in influencing both heart health and metabolic health through three primary mechanisms, including inflammation control, blood sugar regulation, and lipid (cholesterol) management. Several dietary patterns have gained attention over the past few years, particularly for heart and metabolic health. Low-carb and low-fat diets are two popular diets that have gained attention and may have their own pros and cons. While both approaches can be effective, there has been a long-standing debate about low-carb vs. low-fat diets. However, a recent study can help you choose the best one.

Low-carb vs low-fat: Which one is better?

A study, published in the Journal of the American College of Cardiology (JACC) on11 February 2026, settles a long-standing debate about low-carb vs. low-fat diets. The study indicates that it isn't just about the amount of carbs or fat you eat, but the quality of the food that actually protects your heart. Both diet types were associated with a 15% lower risk of coronary heart disease only when they emphasised high-quality, plant-based foods rather than refined carbs or animal products.

For the study, researchers followed nearly 200,000 adults in the U.S. for over 30 years. They examined whether people who chose low-carb or low-fat diets actually had fewer heart attacks or heart disease.

The study looked at how these different food choices changed biological markers like cholesterol, inflammation and long-term heart health.

Researchers found that a low-carb or low-fat label doesn't mean much on its own.

"Our findings highlighted that it's not simply about cutting carbs or fat, but it's about the quality of foods people choose to construct those diets," Zhiyuan Wu, a postdoctoral research fellow at the Harvard T.H. Chan School of Public Health and lead author of the study, said in a press statement.

"The efficacy of low-carb and low-fat diets in reducing CHD risk is a topic of ongoing debate, and past studies showed mixed findings. Focusing only on nutrient compositions but not food quality may not lead to health benefits," Wu continued.

Major findings include:

1. Quality matters

Both healthy low-carb and healthy low-fat diets significantly reduced the risk of heart disease. These diets focused on:

• Plant-based proteins
• Healthy fats
• Whole grains (for low-fat) or fibre-rich veggies (for low-carb)

People who followed unhealthy versions of these diets, even if they successfully kept their carbs or fat low, had a higher risk of heart disease. These versions were heavy in:

• Refined sugars and white bread
• Processed meats and animal fats

2. They change your biology similarly

The study used metabolomics and found that when people eat high-quality food, their bodies show similar positive changes, regardless of whether they are on a low-carb or low-fat plan. These include:

• Lower triglycerides
• Higher good cholesterol (HDL)
• Less inflammation, which is a major driver of heart attacks

Since both high-quality low-carb and high-quality low-fat diets led to similar heart benefits, the researchers concluded that there is no one-size-fits-all diet.

If you are trying to protect your heart, don't just focus on cutting out bread or cutting out oil. Instead, focus on where your food comes from. Swapping processed meat and refined sugar for plant-based foods and healthy fats is the most effective way to lower your risk, regardless of which diet trend you follow.

Ultimately, the choice between a low-carb or low-fat diet depends on individual lifestyle, preferences, and health goals. It is essential to focus on the overall quality of the diet rather than being strict about macronutrient ratios. Consulting a professional or a registered dietitian can help tailor dietary choices to support optimal heart and metabolic health.

Disclaimer: This content including advice provides generic information only. It is in no way a substitute for a qualified medical opinion. Always consult a specialist or your own doctor for more information. NDTV does not claim responsibility for this information.