Is intermittent fasting increasing the risk of heart attacks?

Skipping meals to shed weight or stay “healthy” has become a big trend in recent years. Intermittent fasting (IF), where people eat only during certain hours of the day or take long breaks between meals, is often praised as a quick fix for better health.

But a new study has raised eyebrows. Researchers suggest that while intermittent fasting may help some people, it could also raise the risk of heart problems, including heart attacks, by a whopping 135 per cent.

But why is cardiovascular health linked to intermittent fasting? What should you be doing? Let’s break it down.

But first, how does intermittent fasting work?

Intermittent fasting isn’t a diet in the traditional sense. It doesn’t tell you what to eat but rather when to eat.

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People follow it in different ways. Some keep all their meals within an 8, 10, or 12-hour window and fast the rest of the day.

The most common version is the 16:8 method, which is fasting for 16 hours and eating all meals within an 8-hour window. Others prefer alternate-day fasting or even 5:2 fasting, where they eat normally for five days and restrict calories for two.

The idea is simple: by giving your body longer breaks without food, you can tap into fat stores, improve metabolism, and potentially support long-term health. And for many, it works, at least in the short term.

Also read: Is intermittent fasting bad for your hair?

How does intermittent fasting affect heart health?

A new study published in the journal Diabetes and Metabolic Syndrome has raised questions about how intermittent fasting might affect the heart.

Researchers tracked American adults over eight years and asked them to recall everything they ate and drank on two separate days, about two weeks apart. Using this data, scientists estimated each person’s average eating window and treated it as representative of their long-term habits.

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The findings were striking. Researchers, analysing data from more than 19,000 adults, found that people who ate within an eight-hour window had a 135 per cent higher risk of dying from cardiovascular diseases, such as heart attacks or strokes, compared to those who spread their meals over 12 to 14 hours.

The researchers also checked for links with cancer and overall mortality but found none. What stood out was the strong association with cardiovascular disease, which held true across eight different groups, including race, ethnicity, and socioeconomic background.

The link also remained even after adjusting for factors such as diet quality, frequency of meals and snacks, and other lifestyle habits, BBC reports.

Still, the authors caution that the findings don’t prove fasting directly causes heart problems. More long-term trials are needed to know for sure.

“Although (there could be confounding factors), people should be extremely cautious to adopt a short eating window for a long time over years to pursue cardiovascular health or longevity, which has no evidence support from human studies to date,” said Victor Wenze Zhong, senior author of the study.

Also read: Food for Thought: Can intermittent fasting increase the risk of cancer?

Not a one-size-fits-all solution

Other experts say intermittent fasting does have benefits, but with caveats.

On the plus side, it’s been shown to help with weight loss, improve insulin sensitivity, lower blood pressure, and even reduce inflammation. “However, the potential downsides include nutrient deficiencies, increased cholesterol, excessive hunger, irritability, headaches and reduced adherence over time,” Prof Anoop Misra, a leading endocrinologist, told the BBC.

He added that for people with diabetes, fasting without medical guidance could cause dangerous drops in blood sugar. For older adults or those with chronic illness, it might worsen frailty or speed up muscle loss.

Dr Ranjan Shetty, lead cardiologist at Sparsh Hospital, Bengaluru, also warned that it’s not just about the kilos.

“If a person is obese, then the weight drop will still settle at an acceptable limit. It may not be the same for another person who is not that overweight. What you have to watch out for is loss of lean muscle mass. Intermuscular fat is bad news for the heart,” he told The Indian Express.

For now, experts suggest fasting shouldn’t be seen as a blanket solution. The best approach is one tailored to your health, lifestyle, and risks. Until more evidence is in, the advice is simple: pay less attention to the clock, and more to what’s on your plate.

With input from agencies