Weekend binges just as bad for the gut as a regular junk food diet, study suggests

OFTEN find yourself eating slim on weekdays, but leave the healthy drive at work to be replaced by a two-day weekend junk-a-thon?

Well, new research from the University of New South Wales has revealed that five days of good eating, mixed with two days of bad bingeing is just as detrimental to your gut as a consistent diet of junk food.

The study, which examined the impact of yo-yo dieting on the guts of rats, was the first of its kind to compare how continuous or intermittent exposure to an unhealthy diet could affect the composition of gut microbiota, the cells and organisms in our intestines.

Professor Margaret Morris, who led the research, said the study revealed that the good work we do during the week may come undone if a dieter indulges over the weekend.

“While these findings are yet to be replicated in humans, those who are strict with their diet during the week may be undoing all their good work by hitting the junk food over the weekend,” Ms Morris said.

The study, which fell over 16 consecutive weeks, focused on three groups of rats, each living on a different food diet.

“We compared animals who ate junk continuously, compared to a group who had a bad diet three days a week and then the final group lived on a low-fat diet across the course of the study,” Prof Mossis.

“We found similar results relating to gut microbiota were seen with the rats who had a full junk diet, and those who simply ate badly over three days.

“Those eating the high fat for 16 weeks straight put on the most weight — about 30 per cent more than the controlled group, who had four days good food and three days of junk.

“Although the weight gain was higher in the rats who indulged in junk food over 16 weeks, the research revealed the damage to the gut microbiota stayed the same.
“The findings indicate that intermittent exposure to junk food three days a week is sufficient to extensively shift the gut microbiota towards the pattern seen in obese rats consuming the diet continuously.”

Despite the research linking the role of gut microbiola and our weight status, nutritionist Kristen Beck said it was important to note the impact different eating patterns had on health.

“It is important to note that similar findings are yet to be replicated to humans so need to be interpreted with caution,” she said.

“This study is focusing on the requirements of the gut microbiota — not our own body’s nutritional requirements.

“Our digestive systems contain trillions of different microbial cells, or ‘good’ and ‘bad’ bacteria. Some species have been observed to actually help you to maintain a healthy body weight.

“This study is focusing on the health of our gut microbiota only. We still need to eat a variety of healthy foods, like vegetables, fruits, nuts, seeds, whole grains, fish, legumes, lean meat and dairy products every day in order to reach our nutritional requirements.”

So how should the study influence a dieters habit?

“Hopefully, a person who eats healthy during most of the week, but likes to ‘relax’ and eat more junk foods on the weekend would still continue to eat healthy foods over the weekend as well,” Ms Beck said.

“The worst thing you can do with junk food is eat it mindlessly. If you have particular junk food indulgences that you really love — by all means enjoy them, just limit and savour them — then get back to filling up on all of the healthy foods that provide us with vital nutrients and feed our beneficial bacteria.”

The next phase of Prof Morris’s obesity and diet-related research is looking at the links between the brain, behaviour and the gut’s microbiota.