Intermittent fasting linked to higher risk of death from heart disease: US study

Have you jumped on the intermittent fasting bandwagon?

Here's some negative health risks news you might want to consider.

It turns out, those who limit their consumption of food to less than eight hours a day faced a 135 per cent higher risk of dying from cardiovascular disease, related to issues with the heart and blood vessel, compared to those who ate over 12 to 14 hours.

An August 2025 study published in the Diabetes & Metabolic Syndrome: Clinical Research and Reviews suggests that intermittent fasting could lead to fatalities resulting from heart disease.

The possible health risks posed for some groups of people was due to cardiovascular risks.

135 per cent risk of dying from heart disease

The research did not directly prove that practising intermittent fasting increases the likelihood of death.

It did find a weak and inconsistent link between time-restricted eating and overall deaths, with the risk of dying from cardiovascular disease sharply higher.

In the study, 19,831 adult participants in the U.S. were monitored for their daily food intake habits over eight years.

To understand their eating habits, participants were asked on two separate days, roughly every two weeks, to recall everything they ate and drank.

Scientists estimated each person's average eating window and extrapolated, treating it as representative of their long-term routine.

Increased cardiovascular risk was especially pronounced among smokers, people with diabetes, and those already living with heart disease.

Some groups of people should approach intermittent fasting with caution

Victor Wenze Zhong, lead researcher and epidemiologist at Shanghai Jiao Tong University School of Medicine, advised individuals with heart disease or diabetes to approach short eating windows with caution, according to BBC.

The results highlight the importance of tailoring dietary guidance to each person's health profile and the latest scientific evidence.

While the study uncovered a sharp rise in heart-related deaths among those on very narrow eating schedules, the link to overall mortality remains weaker and inconsistent, especially with all-cause and cancer mortality cases.

What it means for intermittent fasting enthusiasts

These findings may raise questions among followers of the diet, many of whom adopt short eating windows.

However, experts urge not to over-interpret these results.

They highlighted that there were observational limits, and that associations do not equal causation.

This means that eating within a short window may merely correlate with other risk factors.

There are also diverse fasting practices in the diet and may incorporate healthy routines like balanced nutrition, stress management, and regular exercise.

More robust studies are also required to determine whether observed risks persist when accounting for variables like socioeconomic status, diet quality, physical activity, and pre-existing conditions.

How intermittent fasting works

Intermittent fasting involves eating all meals within a limited window of time per day — typically about eight hours — followed by a 16-hour fasting period, according to BBC.

There are also plans, such as the 5:2 diet, which involve cutting calories on certain days of the week, rather than restricting eating hours.

According to Harvard Health Publishing, the diet is believed to be able to curb one's appetite by slowing the body's metabolism.

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