Snacking at night raises risks of breast cancer and diabetes

A night time snack might seem like a harmless treat, but a new study suggests it could raise the risk of breast cancer and diabetes.

Researchers have discovered that fasting at night is crucial for good health and people who snack in the early hours are putting themselves at risk of disease.

It is the first study to show that nocturnal eating should be avoided to allow the body’s metabolism to work in alignment with natural sleep-wake cycles.

Eating regular meals at set times and then waiting longer between dinner and breakfast appears to regulate blood sugar and lower risk of illness.

For every three hours of extra fasting at night women were 20 per cent less likely to have hyperglycemia - or high blood sugar - a known risk factor for breast cancer and diabetes.

"Increasing the duration of overnight fasting could be a novel strategy to reduce the risk of developing breast cancer,” said lead author Catherine Marinac, a doctoral student at University of California, San Diego School of Medicine.

"This is a simple dietary change that we believe most women can understand and adopt. It may have a big impact on public health without requiring complicated counting of calories or nutrients."

Previous studies have shown that women who are diagnosed with type 2 diabetes have a 23 per cent higher risk of developing breast cancer.

Night shift workers have an increased risk of breast cancer and the study suggests it could be a result of deregulated eating patterns.

More than 2,000 women took part in the study and were asked to record their eating and sleeping patterns between 2009 and 2010.

Those who reported longer fast durations also indicated they consumed fewer calories per day, ate fewer calories after 10 pm and had fewer eating episodes.

Dr Ruth Patterson added: "The dietary advice for cancer prevention usually focuses on limiting consumption of red meat, alcohol and refined grains while increasing plant-based foods.

"New evidence suggests that when and how often people eat can also play a role in cancer risk.

“To our knowledge this is the first study to document that longer night-time fasting duration in women was significantly associated with improved glycemic regulation and putatively with reduced breast cancer risk.

“If this findings are confirmed, recommendations for prolonged nightly fasting could be provided as a simple and understandable dietary guideline.”

However breast cancer charities warned against changing eating times until further studies have been carried out.

“As the researchers did not assess the breast cancer risk of the women taking part in this study the claim that the length of time fasting overnight could affect a person’s breast cancer risk is unfounded, 2 said Katie Goates, Senior Research Communications Officer at Breakthrough Breast Cancer and Breast Cancer Campaign.

"The researchers also highlight that no other studies have proven a link between longer periods of night-time fasting, its resulting influence on the body’s glucose uptake and breast cancer risk.

“In the meantime, we already know that there are various things that women can do to help reduce their risk of developing the disease, such as maintaining a healthy weight, limiting the amount of alcohol they drink and leading an active lifestyle."

The research was published in the journal Cancer, Epidemiology Biomakers and Prevention.

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