Intermittent Fasting and Heart Disease: What You Should Know

Intermittent fasting has been a popular weight-loss method for several years, and losing weight tends to be good for heart health if you have obesity or overweight. But if you follow the news, you might have heard that research presented at a recent meeting of the American Heart Association (AHA) suggests going for long stretches without eating might be harmful for your heart.

So what's the right move?

For the unfamiliar, intermittent fasting is a pattern of only eating during a set period. One of the most popular styles is time-restricted eating, where you restrict eating to certain hours of the day, like from 10 a.m. to 6 p.m (aka, 16:8 fasting).

Kenneth Saland, MD, an interventional cardiologist with Texas Health Presbyterian Hospital Dallas and Texas Health Physicians Group, recommends intermittent fasting to some of his patients but acknowledges that it may not be the right approach to weight loss for everyone.

Here's what you should know about how intermittent fasting may affect heart health — and how to make the right choice for you.

There's a large body of evidence to show that intermittent fasting can support heart health. A March 2024 umbrella review looking at 23 meta-analyses and reviews of intermittent fasting studies, published in ‌eClinical Medicine‌, found that intermittent fasting can lower heart disease risk factors including:

• LDL ("bad") and total cholesterol
  
• Triglycerides
  
• Blood pressure
  
• Fasting insulin
  

Many of these benefits come down to the fact that intermittent fasting helps people lose weight and decrease their waist circumference.

"For people of a higher weight who may have other risk factors for heart disease, a modest weight loss may help reduce risk to some degree," says Devon Hoster, RD, LDN, a dietitian who focuses on heart health.

More may be at play though. Taking breaks from eating gives your body a chance to use up its blood sugar or fuel that's stored in the liver, says Dr. Saland. "As you fast and exercise, you use it up, and when that goes away, you start breaking down stored fat," he says.

This process also encourages healthy hormone regulation (like insulin) and reduces inflammation by giving your cells and blood vessels a chance to repair damaged tissue, according to July 2023 research in ‌Advances in Nutrition.‌

Despite these benefits, the research presented at a March 2024 meeting of the AHA found that people who followed a 16:8 time-restricted eating schedule were about twice as likely to die from heart disease compared to people who followed a standard eating schedule. Yikes.

While the findings might sound concerning, this single study shouldn't deter people from trying intermittent fasting if they're interested, say both Dr. Saland and Hoster.

"This was an observational study, not a super rigorous thing," Dr. Saland says. "If you look at the groups [in the study], one group had more men and more smokers," both of which have a higher risk of dying from heart disease regardless of diet, he adds.

Hoster agrees that it's hard to make sweeping statements from a single study. "We can't really determine direct cause and effect due to such variability of health history and lifestyle factors in the study population," she says.

Also important to consider: Intermittent fasting is the way that humans evolved to eat over hundreds of thousands of years, so in general, it's unlikely to cause major health problems. "Intermittent fasting is really part of our biology. Historically we weren't eating and grazing all day long, so our bodies had to adapt and be able to break down our stored fat," Dr. Saland says.

There's no one-size-fits-all eating plan that works for everyone. That said, intermittent fasting can be an option to help you lose weight if you're trying to lower your risk for heart disease, heart attack or stroke.

"In some cases, decreasing the window of time during which food is consumed may aid in weight loss, provided that the patient's diet quality is nutrient-dense," Hoster says.

But it's not the only option. Traditional calorie restriction (aka, eating fewer calories without worrying about timing) can also help you lose weight, reduce your insulin sensitivity and lower your blood pressure and cholesterol, according to an April 2020 paper in the ‌The American Journal of Medicine‌.

Ultimately, it's about finding an eating plan that works for you and that you can stick with long-term to reach and maintain your goals, Dr. Saland says. Your health care provider can help you make the right choice.

Intermittent fasting isn't right for everyone, so check with your doctor before giving it a try. They may recommend trying a different eating plan if you:

• ‌Have certain chronic conditions.‌ Intermittent fasting isn't the right fit you take medication for diabetes, have a history of low blood sugar or have an eating disorder, notes the Mayo Clinic.
  
• ‌Are on medications that should be taken with food.‌ It may be harder to stick to your recommended dosing schedule if your eating times are limited, Hoster says.
  
• ‌Are pregnant or nursing.‌ Intermittent fasting might affect your blood sugar or make it harder to get the calories your body needs.
  
• ‌Just don't like it.‌ Some people find that limiting their eating to a short window causes them to get hungry and overeat later, "which may end up hindering their weight-loss efforts," says Hoster. Others might notice that fasting gives them headaches and mood swings or makes them feel dizzy. If that's the case for you, try something else.
  

Whether you decide to try intermittent fasting, traditional calorie restriction or another approach to lose weight, ‌what‌ you eat is of paramount importance. The good news is, making heart-healthy eating choices that help you achieve a healthier size doesn't have to be complicated.

Here's what Hoster recommends:

• ‌Focus on whole foods, not "superfoods."‌ Fruits and vegetables, whole grains, beans and legumes, lean proteins (like beans, poultry, seafood, eggs, tofu and nuts), reduced-fat dairy and healthy fats are the building blocks of any healthy eating plan. "The seemingly 'basic' or 'boring' nutrition tips are actually the most practical when it comes to heart-healthy eating," she says.
  
• ‌Watch your salt.‌ Excess sodium can raise your blood pressure, but cutting out just 1,000 mg of sodium per day can improve your heart health, notes the AHA. (The AHA recommends no more than 2,300 mg/day — about 1 teaspoon of table salt.) Be mindful of the salt shaker, but also watch for other sneaky sources of sodium. "Sodium is often found in many premade foods and can be quite high in restaurant foods," Hoster says. Check packaged food labels and try to cook at home most of the time.
  
• ‌Choose healthier fats.‌ Opt for heart-healthy sources like olive oil, avocados, nuts and seeds. They're better for your heart than foods high in saturated fats like butter, fried foods, full-fat dairy and fatty red meats.