Is Eating Low Fat or Low Carb Better for Heart Health? Trick Question

“There isn’t a one-size-fits-all diet but rather multiple pathways to achieving heart health when the focus is on quality,” says Grace A. Derocha, RD, CDCES, a Detroit-based spokesperson for the Academy of Nutrition and Dietetics.

Why Diet Quality Matters Most

• Healthy low-carb and low-fat diets both reduce the risk of heart disease.
• Low-carb and low-fat diets may contain unhealthy foods — bacon in a low-carb diet, for example, or snacks with added sugars in a low-fat diet — that are not dense in nutrients and could increase the risk of heart disease. These include foods with added fats and salt.
• Although the diets look very different on paper, your body responds to good versions of them in similar, heart-friendly ways.

This may explain why the debate between the benefits of a low-fat diet versus a low-carb diet has not had a clear winner.

“In practice, I see that when individuals focus on whole, minimally processed foods, their cholesterol, blood sugar, and inflammatory levels often improve, regardless of whether they identify as following a low-carb or low-fat diet approach,” Derocha says.

The reason? High-quality ingredients.

"Low-carb and low-fat diets that are considered healthy have similar characteristics,” says Sean Heffron, MD, a preventive cardiologist and the director of cardiovascular fitness and nutrition at the Center for the Prevention of Cardiovascular Disease at NYU Langone Health in New York City.

Both diets, Dr. Heffron says, are rich in potentially beneficial antioxidants and nutrients from these sources:

• Fruits and vegetables
• Whole grains
• Seafood

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• Nuts
• Seeds

These higher-quality foods support heart health by improving key biomarkers such as lowering triglycerides, raising HDL (“good”) cholesterol, and reducing inflammation, says Zhiyuan Wu, PhD, a study co-author and postdoctoral research fellow at the Harvard T.H. Chan School of Public Health in Boston. This is largely because of the healthy fats, antioxidants, and anti-inflammatory compounds found in whole, plant-based foods, he says.

“Regardless of whether someone follows a low-carb or low-fat diet, choosing higher-quality foods helps the body regulate fat and inflammation more effectively, which likely explains the healthier biomarker profile we observed,” Dr. Wu says.

Conversely, you can easily find low-quality ingredients to eat within the framework of each diet. The secret, researchers say, is finding the balance between the positives of each approach.

Low Fat: Benefits and Risks

“Over time this can contribute to insulin resistance, elevated triglycerides, and increased inflammation, all of which are risk factors for heart disease,” Derocha says.

Low Carb: Benefits and Risks

• Lose weight
• Reduce triglycerides
• Lower blood pressure
• Increase HDL cholesterol

Where they can go wrong is in removing carbs in favor of saturated fat that increases LDL cholesterol and your risk of heart disease, Derocha says.

“They tend to entice people by telling them that since they aren’t eating carbs, they need to eat lots of protein and fat — and that means high saturated-fat foods like beef, pork, and bacon that people should be avoiding,” Heffron says.

Designing a Heart-Healthy Diet

“A heart-healthy approach doesn’t require choosing sides between carbs or fats,” Derocha says. “It’s about building a balanced, sustainable pattern centered on food quality.”

Here are the key strategies she recommends:

• Use whole, minimally processed foods as the foundation of your meals.
• Prioritize fiber-rich carbohydrates such as legumes, whole grains, vegetables, and fruits.
• Choose healthy fats, such as those found in nuts, avocados, and olive oil.
• Limit refined carbohydrates, added sugars, and highly processed foods.
• Incorporate lean protein sources, including fish and plant-based options like beans, soy, and seeds.

Always talk to your doctor and healthcare team before making any significant changes to your diet. Also note that with any healthy eating plan, consistency often matters more than perfection.

“Small, sustainable changes like swapping refined grains for whole grains or adding more vegetables to meals can have a meaningful impact on heart health over time,” Derocha says.

The Takeaway

• Low-carb and low-fat diets can be either healthy or unhealthy, depending on the quality of the foods you choose.
• Low-fat diets can be effective in removing unhealthy saturated fat, but the addition of refined carbohydrates in low-fat or nonfat foods may negate the diets’ positive effects.
• Low-carb diets such as Atkins, paleo, and keto can help you lose weight but may reintroduce animal fats that can pose cholesterol and heart risks.
• The quality of ingredients matters more than the amount of fat or carbohydrates you consume. Choose whole, minimally processed foods like fruits, vegetables, whole grains, lean protein, and healthy fats.