While following a ketogenic diet, which consists of ingesting almost all of your calories from fat and very little from carbohydrates, can help you lose weight, it can also damage your gut microbiota and block your arteries.
This eating style, also referred to as a keto diet, compels the body to use an alternative fuel. It begins to rely on ketone bodies, a form of fuel the liver creates from stored fat, rather than glucose from carbs, which causes weight loss.
Studies in the past have compared the health outcomes of individuals following a ketogenic diet to those who do not, suggesting that there may be drawbacks as well as advantages.
The best type of medical proof has now been conducted by Javier Gonzalez and his colleagues at the University of Bath in the UK through a randomised controlled experiment. 53 participants, with an average age of 34, were gathered by the researchers; none of them were obese. Roughly one-third of the participants were randomized at random to follow a ketogenic diet, which consisted primarily of fat intake (more than 70%) and less than 8% of all carbohydrates.
A further third were instructed to follow a low-sugar diet in which their intake of fat and non-free sugar carbohydrates was restricted to 35 percent and 45 percent, respectively, while their intake of "free" sugars, a form of carbohydrate, which may be found in foods like syrups, cakes, and biscuits, accounted for five percent of their total calorie intake.
The remaining third consumed small quantities of free sugars, which accounted for little less than 20% of their total calorie intake. In contrast, they consumed roughly 30% and 35% of their energy from non-free sugar carbohydrates and fats, respectively. The control group consisted of these individuals. The range of protein consumption in each diet was 15% to 18%.
X-rays taken a month later showed that, on average, those following the ketogenic diet had reduced 1.6 kg of fat. By testing the amounts of ketone bodies in the individuals' blood, urine, and breath, the team was able to determine that they had adhered to the ketogenic diet. Diet adherence was also measured via food diaries.
On average, people following a low-sugar diet went on 1 kg of fat, but people following a normal diet had no weight loss. The researchers discovered—unclearly at first—that the subjects' weight loss was due to calorie restriction rather than increased exercise by having them wear movement trackers on and off for different periods.
Although the ketogenic group lost more weight than the control group, their levels of low-density lipoprotein (LDL), or "bad" cholesterol, were 16% higher. Additionally, their levels of apolipoprotein B, a protein that clogs arteries and increases the risk of heart-related incidents, were 26% higher. As opposed to individuals in the control group, those following a low-sugar diet experienced a 10% decrease in LDL cholesterol and no change in apolipoprotein B levels.
Additionally, the researchers discovered that the individuals following the ketogenic diet only had lower levels of Bifidobacterium, a form of gut flora related to a stronger immune system and which aids in the production of B vitamins, when compared to those following the moderate-sugar diet. According to Gonzalez, this is most likely because people who followed a low-carb diet consumed less fiber, which raises Bifidobacteria levels.
However, it's uncertain whether a ketogenic diet hurts the gut microbiome because it's unclear what the full impacts of Bifidobacteria or what defines an ideal diet are, according to Natasha Schoeler of Great Ormond Street Hospital in London.
Furthermore, according to Schoeler, elevated cholesterol levels are not always hazardous if they fall below critical thresholds, even when elevated apolipoprotein B is problematic.
According to Schoeler, long-term studies are necessary to ascertain whether the advantages of a ketogenic diet for weight loss outweigh any potential risks to gut health and cholesterol in obese individuals.
Following a diet is ultimately the biggest obstacle to weight loss for those who are obese or overweight, according to Schoeler. “Whether it is a normal-carbohydrate diet, but low in calories, or the same amount of calories with less carbohydrate – if you stick to it, generally, you will lose weight,” she says.
