Published in Cell Reports Medicine, the research from the Centre for Nutrition, Exercise, and Metabolism involved 53 healthy adults for up to 12 weeks. Participants followed either a moderate sugar diet (control), a low-sugar diet (less than 5% of calories from sugar), or a ketogenic (keto) low-carbohydrate diet (less than 8% of calories from carbohydrates).
Key findings include:
Increased Cholesterol: The keto diet raised cholesterol levels, particularly in small and medium sized LDL particles. The diet increased apolipoprotein B (apoB), which causes plaque buildup in arteries. In contrast, the low-sugar diet significantly reduced cholesterol in LDL particles.
Reduced Favourable Gut Bacteria: The keto diet altered gut microbiome composition, notably decreasing Bifidobacteria, beneficial bacteria often found in probiotics. This bacteria has wide ranging benefits: producing b vitamins, inhibiting pathogens and harmful bacteria and lowering cholesterol. Sugar restriction did not significantly impact the gut microbiome composition.
Glucose Tolerance: The keto diet reduced glucose tolerance, meaning the adults’ bodies became less efficient at handling carbohydrates.
Both Diets Resulted In Fat Loss: Keto Diet resulted in an average of 2.9 kg fat mass loss per person, whilst the sugar restricted diet followed with an average 2.1 kg fat mass loss per person at 12 weeks.
Metabolism: Researchers also noticed that the keto diet caused significant changes in lipid metabolism and muscle energy use, shifting the body’s fuel preference from glucose to fats.
Physical Activity Levels: Both sugar restriction and keto diets achieved fat loss without changing physical activity levels. Previous studies from the Centre for Nutrition, Exercise and Metabolism have shown that skipping breakfast or intermittent fasting cause reductions in physical activity.
Lead researcher Dr. Aaron Hengist highlighted the concerning cholesterol findings:
“Despite reducing fat mass, the ketogenic diet increased the levels of unfavourable 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.”
Dr. Russell Davies, who led the microbiome research, explained the impact on gut health:
“Dietary fibre is essential for the survival of beneficial gut bacteria like Bifidobacteria. The ketogenic diet reduced fibre 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.”
Source: https://www.sciencedaily.com/
