Fat and struggling to lose weight? Scientists think they’ve discovered why – and it all has to do with your brain

Many people who carry a few pounds suspect that it is more difficult for them to lose weight than their slim friends.

This may even be true, as there is some evidence that overweight people have changes in their brains that make it harder for them to know when they are full.

The findings come from brain scans of 1,351 people, which showed that those who were overweight or obese had a larger hypothalamus.

The hypothalamus is an important part of the brain involved in regulating appetite.

The results of the MRI scan suggest that overweight people have three enlarged areas of the hypothalamus that are involved in picking up signals from the gut to say ‘you’re full, stop eating’.

This enlargement can prevent the signals from getting through properly – so that dieting really becomes more difficult for people who are already overweight.

Dr. Stephanie Brown, who led the study from the University of Cambridge, said: ‘This research helps us understand more about the changes in the brain that take place in overweight or obese people – our brains and biology can make it difficult to lose weight. .

‘If what we see in mice is also the case in humans, then eating a high-fat diet may cause inflammation of our appetite control center.

“Over time, this would change our ability to tell when we’ve eaten enough and how our body processes blood sugar, causing us to gain weight.”

The many hormone signals sent from the gut to the brain that tell us when we’re hungry and full are famously temperamental.

People can get stuck in a vicious cycle, where overweight people end up with a bigger hypothalamus, causing them to overeat, which changes the hypothalamus even more so they eat even more, experts say

For example, a lack of sleep disrupts the system, leaving us more hungry than we should be.

And the “hungry” and “full” hormone signals may also be disrupted by a larger hypothalamus – based on studies where mice with changes in the hypothalamus ate more food before realizing they were full.

If this also happens in humans, it could help explain why people with a larger hypothalamus were more likely to be overweight in the new study.

But mouse studies also suggest that being overweight is what causes the hypothalamus to swell in the first place — this happened after just three days on a high-fat diet.

If that’s the case with humans too, they could end up in a vicious cycle where overweight people get a bigger hypothalamus, causing them to overeat, which changes the hypothalamus even more so they eat even more.

But the human study didn’t directly show this, meaning a lot more research is needed.

Researchers want to understand whether the changes in the hypothalamus of overweight people are due to their diet activating immune chemicals that then accumulate at the barrier that separates the brain from the rest of the body.

This can cause a buildup of glial cells in the brain that clear out waste, which can then damage healthy cells, making the hypothalamus less able to receive the “hungry” and “full” signals from hormones in the gut.

It can also make it less able to process insulin – the hormone that regulates blood sugar – which can also lead to additional weight gain.

The study looked at people ages 18 to 40 and compared the brains of those of a healthy weight, overweight, with a BMI over 25, and obese, with a BMI over 30.

The higher a person’s BMI on average, the larger their hypothalamus.

Normally the hypothalamus which is about the size of an almond is too hard to see with an MRI machine because the brain tissue it contains is too similar so there isn’t much light or shadow in the image of the brain scan.

But researchers used a high-tech algorithm that makes it clearer to see by identifying different cell types.

WHAT SHOULD A BALANCED DIET LOOK LIKE?

Meals should be based on potatoes, bread, rice, pasta or other starchy carbohydrates, ideally whole grains, according to the NHS

• Eat at least 5 servings of different fruits and vegetables every day. All fresh, frozen, dried and canned fruit and vegetables count

• Basic meals based on potatoes, bread, rice, pasta or other starchy carbohydrates, preferably whole grains

• 30 grams of fiber per day: This is equivalent to eating all of the following: 5 servings of fruits and vegetables, 2 whole-wheat muesli biscuits, 2 thick slices of whole-wheat bread, and a large baked potato with skin

• Provide dairy or dairy alternatives (such as soy drinks) and choose lower-fat, lower-sugar options

• Eat some beans, legumes, fish, eggs, meat and other proteins (including 2 servings of fish per week, one of which is fatty)

• Choose unsaturated oils and spreads and consume in small quantities

• Drink 6-8 cups/glasses of water per day

• Adults should have less than 6 g of salt and 20 g of saturated fat for women or 30 g for men per day

Source: NHS Eatwell Guide