Eating a ketogenic diet dietwhich involves consuming most calories from fat and very few from carbohydrates, leads to fat loss, but can also clog arteries and negatively affect the gut microbiome.
Also known as the ketogenic diet, this way of eating forces the body to use a different type of fuel. Instead of relying on glucose from carbohydrates, it begins to rely on ketone bodies, a type of fuel that the liver produces from stored fat, leading to weightloss.
Previous studies have tracked health outcomes in people who follow a ketogenic diet compared to those who do not, suggesting that they have both harms and benefits.
Now, Javier Gonzalez At the University of Bath in the United Kingdom, a team of researchers conducted a randomized controlled trial, the best medical test. The researchers recruited 53 people with an average age of 34, none of whom were obese. They randomly assigned about a third of them to follow a ketogenic diet, in which all types of carbohydrates accounted for less than 8 percent of their energy intake and fat made up more than 70 percent.
Another third of participants were told to eat a low-sugar diet, where “free” sugars – a type of carbohydrate found in foods such as syrups, cakes and cookies – made up 5 percent of their energy intake, while their intake of non-free carbohydrates and fats was 45 percent and 35 percent, respectively.
The remaining third consumed a diet with moderate levels of free sugars, which accounted for just under 20 percent of their energy intake, while their intake of non-free carbohydrates and fats was around 30 and 35 percent, respectively. These participants acted as a control group. Protein consumption ranged from 15 to 18 percent across all diets.
One month later, X-rays revealed that participants on the ketogenic diet had lost 1.6 kilograms of fat, on average. The team confirmed that participants had followed the ketogenic diet by measuring levels of ketone bodies in their blood, urine and breath. Food diaries also measured adherence to the diet.
Meanwhile, those on the low-sugar diet lost 1kg of fat, on average, while those on the moderate diet lost no fat. By having participants wear motion monitors intermittently and estimating their energy intake, the team found that the fat loss was due to consuming fewer calories, rather than exercising more – something that had been unclear until now, Gonzalez says.
But while there was greater fat loss in the ketogenic group, these individuals had 16 percent higher levels of “bad” low-density lipoprotein (LDL). cholesterol Compared with the control group, participants had 26 percent higher levels of a protein called apolipoprotein B, which clogs arteries and increases the risk of heart problems. In contrast, participants on the low-sugar diet had 10 percent lower levels of LDL cholesterol and no changes in their apolipoprotein B levels compared with those in the control group.
The researchers also found that compared to the moderate-sugar diet, those on the ketogenic diet had reduced levels of a type of gut bacteria called Bifidobacteriawhich helps produce B vitamins and It has been linked to a stronger immune system.. The same did not happen with those who followed the low-sugar diet. This is probably because those who followed the ketogenic diet consumed less fiber, which increases Bifidobacteria levels, says Gonzalez.
But it's not clear whether a ketogenic diet actually negatively affects the gut microbiome, because no one is entirely sure what constitutes an optimal diet or what the full effects of Bifidobacteria They are, he says Natasha Schoeler at Great Ormond Street Hospital in London.
Also, while elevated apolipoprotein B levels are concerning, the higher cholesterol levels seen in the study aren't necessarily harmful if they don't reach dangerous thresholds, Schoeler says.
Long-term research is also needed to determine whether the weight loss benefits of a ketogenic diet outweigh potential cholesterol and gut concerns. health among obese people, Schoeler says.
In short, the main challenge of losing weight among those who are obese “If you follow a diet that is normal carbohydrate but low in calories, or the same amount of calories but lower in carbohydrates, generally speaking, if you follow a diet, you will lose weight,” Schoeler says.
Topics: