If you carry a few extra pounds, it may be due to the way your body responds to the food you eat.
Many of us take dietary rules for granted, such as eating little and often, not skipping meals, and monitoring our caloric intake. But genetic epidemiologist Tim Spector argues that we need to reevaluate what we think we know about a good diet.
How did you get to that conclusion?
After verifying that “we are much more different than what we have been led to believe”.
Spector founded the UK Twin Registry at King’s College London to unravel the extent to which our genes contribute to a wide range of human conditions and diseases.
The scientist became interested in why identical twins, with identical genetic makeup, often die from different diseases.
To find the answer, he began studying epigenetics: the power of external factors in the way genes can be turned on and off.
But epigenetics was not enough to explain all the differences.
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The weight between twins, for example, can differ by up to 10 kg.
“We could only explain a small part of that 10kg difference with epigenetics,” Spector told the BBC, “so we knew something was going on that wasn’t due to genes.”
With his team, they searched for another explanation and made a fascinating discovery: “ The only thing they differed in was their gut microbes .”
A chemical factory in the body
The vast repertoire of gut bacteria from two people, even identical twins, is not the same, Spector says.
“If you think of them as an organ in your body that is like a chemical factory, that differs between all of us, suddenly you start to understand why a lot of things in the last 30 years in nutrition have failed.”
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“We all know that some people respond to some diets and others don’t, and yet we have a kind of dogma that we should all be the same and if we don’t lose weight it’s our fault,” he says.
But it’s our unique mix of gut bacteria that dictates our highly individual responses to different foods, he argues.
Microbes against fat
Spector asked the twins in the study to provide stool samples to measure their microbes. They collected many samples, sequenced them, and then looked at twins where one was overweight and the other was thin.
“We found that in all cases the slimmer twin had a more diverse microbiome (more different species), and almost always had a high number of a couple of (types of) microbes that stood out from the crowd,” he says, referring to those of the genus Christensenella and those of the Akkermansia.
“Turns out they are beneficial.”
When they introduced Christensenella into sterile mice, they were able to “stop them from getting fat,” an association that has been confirmed by several other similar projects.
“That shows that a beneficial microbe can affect our intestines to somehow change our metabolism and prevent us from gaining weight.”
“There are probably hundreds of thousands of microbes or strains like that that in combination can have this beneficial effect,” he says.
Most diverse microbes
To ensure we have diverse gut microbes, we need a varied diet, he says.
“After studying 11,000 people, we discovered that optimal diversity is reached if you eat 30 plants a week.”
That sounds like a lot, she admits, but it doesn’t mean you have to drink 30 kale smoothies a week.
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The key is to “go back to biology” and remember what a plant is.
“So is the peanut, the seeds, a little bit of turmeric,” says Spector. “And each plant will help promote the growth of a different set of bacteria or strains of bacteria.”
“It is this diversity of our diet from different unprocessed foods that was the best predictor of a healthy gut. It didn’t matter if you were vegan, vegetarian, (or on) keto or intermittent,” he says.
“This was what you needed to have on your plate. Once you have that, you can do anything else.”
Not all calories are created equal
Spector’s next step was to see how people responded differently to the same foods.
To do this, it co-developed and launched the ZOE app, based in London and Boston, which aims to provide “personalized nutrition.”
The first thing they did was a study in more than 1,000 people, in which, in addition to examining their microbiomes, they monitored the effects on their bodies after eating food.
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They gave participants, for example, an identical muffin, told them to eat it at the same time of day and for the same length of time, and then analyzed glucose measurements and collected information regarding energy levels and appetite.
“We observed large variations between individuals in how their blood sugar levels responded to various foods,” says the epidemiologist.
They found that people whose blood sugar levels dropped significantly two to four hours after eating were more likely to feel hungry earlier and to consume an average of about 300 more calories over the day than those who experienced low blood sugar levels. sugarless pronounced.
The study led Spector and the scientists he worked with to conclude: “We’ve been brainwashed into thinking all calories are the same, but the findings shattered that concept.”
The results, published in the journal Nature Metabolism, “help explain why some people struggle to lose weight, even on calorie-controlled diets and highlight the importance of understanding each person’s unique biology when it comes to diet and health,” according to Zoe’s website.
So, according to this study, if you carry a few extra pounds, no matter how hard you try, it may be due to the way your body responds to the food you eat, rather than its calories.
