Researchers at Penn State University have discovered that high-fat diets, particularly the ketogenic diet, may lead to more serious health issues compared to high-carbohydrate diets. The study, published in the February issue of the Journal of Nutrition, examined the effects of various fat-to-carbohydrate ratios on metabolic health and liver function in mice.
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Mice were divided into groups and fed one of four diets: high carbohydrate, high fat, ketogenic, or a standard chow rich in whole grains that served as a control. Those on the ketogenic diet not only gained weight but also exhibited impaired glucose utilization, disrupted lipid balance, and increased liver inflammation and fat deposits. Conversely, mice consuming the high-carbohydrate diet showed fewer health problems related to liver damage.
Vishal Singh, associate professor of nutritional sciences and senior author of the study, noted that while humans and mice metabolize food differently, this research offers valuable insights. He emphasized that despite the rising popularity of high-fat diets for weight loss, they may cause significant liver harm if not managed properly.
The study involved diets where proteins constituted 18% of total calories, differing only in fat and carbohydrate ratios. The high-fat diet included 40% fat and 42% carbohydrates, while the high-carbohydrate diet had 11% fat and 70% carbohydrates. The high-fat and ketogenic diets were largely composed of saturated fats that, according to the American Heart Association, should be limited to 6% of total calorie intake.
Results indicated that mice on high-fat and ketogenic diets developed obesity, with their weight doubling over the 16-week study period. In contrast, the control group on whole-grain chow gained only approximately 10%. Furthermore, high-fat diets impaired glucose tolerance and damaged liver functionality within two weeks.
Singh warned that individuals attracted to the keto diet for weight loss should consider the potential health risks highlighted by the study. While high-carbohydrate diets are not ideal, they resulted in less liver damage compared to high-fat diets.
In a separate part of the study, obese mice on high-fat diets showed additional weight gain, but those supplemented with fiber while on the keto diet maintained more stable weights and better overall health. Singh mentioned that adding fiber to a keto diet could mitigate gastrointestinal issues while retaining the diet's therapeutic benefits for certain medical conditions, like epilepsy.
Singh concluded that dietary decisions are complex and should be tailored to individual health needs. He advised consulting healthcare professionals for personalized dietary plans.