For people looking to lose weight (and do so quickly) the ketogenic diet, better known as "keto" is a godsend. Originally intended to help people with certain neurological conditions, people on the keto diet eat high-fat, low-carb, and moderate-protein in an effort to lose weight, gain mental clarity, and improve energy levels.
While an array of health benefits have been reported, a recent study published in Cell Reports Medicine reports individuals on a keto diet are experiencing a reduction in friendly gut bacteria in addition to a rise in cholesterol levels.
Over a 12-week-long period, researchers from the Centre for Nutrition, Exercise, and Metabolism at the University of Bath gave 53 participants various diets to see how it may affect their overall health. During this time, the individuals followed either a moderate sugar diet (control), a low-sugar diet (less than 5 percent of calories from sugar), or a low-carb ketogenic diet (less than 8 percent of calories from carbohydrates).
At the end of the 12 weeks, researchers found that not only did the participants on the ketogenic diet experience an increase in small and medium-sized LDL (the "bad" cholesterol), but they also saw a rise in apolipoprotein B (apoB), which is responsible for the plaque buildup in our arteries.
"Despite reducing fat mass, the ketogenic diet increased the levels of unfavorable fats in the blood of our participants, which, if sustained over years, could have long-term health implications such as increased risk of heart disease and stroke," said lead researcher, Dr. Aaron Hengist.
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In addition, they also found that the keto diet altered gut microbiome composition, specifically bifidobacteria, which can help produce important b vitamins, inhibit harmful bacteria, and lower cholesterol levels.
"Dietary fiber is essential for the survival of beneficial gut bacteria like bifidobacteria," said Dr. Russell Davies, who led the microbiome research. "The ketogenic diet reduced fiber intake to around 15 grams per day, half the NHS-recommended intake. This reduction in bifidobacteria might contribute to significant long-term health consequences such as an increased risk of digestive disorders like irritable bowel disease, increased risk of intestinal infection, and a weakened immune function."
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The results weren't all bad, though. The study also discovered that regardless of the participants activity levels both the sugar-restricting diets and ketogenic diets resulted in fat loss, proving that the keto diet may still be a worthwhile way for some individuals to lose weight.
"The ketogenic diet is effective for fat loss, but it comes with varied metabolic and microbiome effects that may not suit everyone," says professor Dylan Thompson, who oversaw the research.
While more research is needed to determine the long-term effects of a keto diet, the researchers agree that if you are going to choose one of the diets they tested to lose weight, the low-sugar ones are a better option for most people.
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