We should all *hopefully* know that what we eat plays an important part in our overall health. It’s practically the first thing we learn in kindergarten: highly processed junk food is bad, whole foods are good. But what many don’t know is that junk food isn’t just bad because of its high-calorie, low-nutrient content, but because it actually triggers changes in your brain that raise your risk of obesity, as a new study has revealed.
No, eating junk food the odd time won’t automatically cause obesity, but the study does illuminate the connection between brain health and diet, and how that link can impact your whole body.
The study
The study in question, which was published in Nature Metabolism, assessed 29 people who were split into two groups. One group spent five days consuming an additional 1,500 calories of highly processed, high-calorie foods. The other group didn’t consume any extra calories, with participants keeping to their regular diets.
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After five days, the researchers found that people in the extra calorie group had a much higher amount of fat in their livers, which isn’t too surprising in and of itself.
What was surprising was that the extra calorie group also suddenly had significantly lower insulin sensitivity once they returned to their regular diet, meaning that their bodies weren’t processing foods as healthily or efficiently as before. Insulin sensitivity is how well the body’s cells respond to insulin, which allows glucose to be converted into energy. Low insulin sensitivity is linked to a higher risk of developing diabetes and obesity.
The researchers concluded that short-term changes in diet can cause the brain to rewire the body’s response to insulin, which can ultimately lead to a higher probability of developing obesity. We already knew that junk food can lead to lower insulin sensitivity, but this study shows just how quickly those changes can occur, given the experiment was only over a five-day period.
What foods lead to lower insulin sensitivity?
Foods that are high in sugars, carbohydrates and unhealthy fats all contribute to lower insulin sensitivity. The study focused specifically on highly processed food with a nutritional breakdown of 47-50 per cent fat and 40-45 per cent carbs.
The researchers also mentioned some of the specific foods that participants were eating during the study. It’s safe to say that no one ever believed that these were healthy foods, but just in case you need another reason to avoid them, they were:
- Snickers
- Brownies
- Chips
- KitKats
- M&Ms
Can low insulin sensitivity be reversed?
Surely five bad days doesn’t mean you’re doomed for life, right? Yes, you can raise your insulin sensitivity, but it’s not a quick process. The exact time it takes to return to normal levels will be different for everyone, but we can all agree that a five-day binge isn’t worth it in the long run.
To raise your insulin sensitivity, eat lots of lean proteins and vegetables, with a mix of protein, fat and fibre at every meal. Regular exercise and good sleep can also help you manage your insulin levels.
In short, don’t write yourself off if you’ve treated yourself to some chocolate or dug into a bag of chips. Junk foods may have negative health effects, but we believe in balance. Treat them always as a ‘sometimes’ food.
