Study under review: Impact of a 6-week non-energy-restricted ketogenic diet on physical fitness, body composition and biochemical parameters in healthy adults
The late 1970s marked the beginning of the obesity epidemic: U.S. obesity rates went from increasing gradually to exponentially over the course of the next two decades. Coincidentally, this rise was accompanied by recommendations to limit the consumption of total dietary fat to avoid heart disease and other ailments. For a long time the USDA food pyramid dictated that carbohydrates (whole grains) should be dietary staples, the Surgeon General recommended that Americans reduce their consumption of foods high in fat, and the National Institute of Health (NIH, 1984) suggested that Americans cut their saturated fat consumption. The overall consensus amongst the American population was that eating fat made you fat.
In recent years the tables have turned and low carbohydrate diets have become a popularized means to induce weight loss. Support behind ketogenic and low carbohydrate diets have been further strengthened by studies demonstrating that carbohydrate restriction can be effective at promoting fat loss. Additionally, ketogenic diets (<10% calories from carbohydrates and >60% of calories from fat) have been shown to be beneficial for decreasing side effects of diseases like epilepsy, and may show some promise in conditions including polycystic ovary syndrome, neurodegenerative diseases, diabetes, and cancer. Despite the growing use of ketogenic diets amongst various disease populations, insufficient evidence exists in non-athletes and athletes to support that ketogenic diets do not negatively impact aerobic and physical performance in healthy individuals.
In the reviewed study, the authors set out to address this research gap by determining the impact of an ad libitum (without caloric restriction), 6-week, ketogenic diet on physical performance, body composition, and blood parameters in healthy adults.
For years, the idea that high fat, low carbohydrate, diets could be beneficial was contested. Although data exists suggesting that ketogenic diets are beneficial for weight loss and certain diseases, there is limited evidence elucidating their effects on physical performance and daily activity. In this study, researchers investigated how 6 weeks of a calorically unrestricted ketogenic diet impacted physical performance, body composition, and blood parameters in healthy men and women.
Other Articles in Issue #30 (April 2017)
Red meat and heart disease: what do controlled trials tell us?
Evidence on saturated fat and heart disease gets updated pretty often, but what’s the state of the evidence on red meat specifically?
If you eat very little one day, do you overeat the following days?
Common wisdom suggests that cutting calories too much on a given day will lead to binging the next day. This trial put it to the test.
Exploring curcumin for depression and anxiety
Depression sucks, and traditional depression treatments aren’t so great either. According to the literature, what effects might curcumin have on this mood disorder?
Let there be light! And vitamin D pills.
People with sub-optimal vitamin D levels have worse cardiovascular health profiles, yet vitamin D supplementation doesn’t seem to help. What gives? This trial aimed to find out.
Control your diet, control your depression?
With all the talk about diet impacting mood and depression, you might be surprised to know that very few controlled trials have investigated those actually diagnosed with depression. Here’s a brand new study.
Where do cravings come from? By Stephan Guyenet, PhD
Stephan is a neuroscientist who has researched the intricate mechanisms behind overeating.
Interview: Luis Villasenor
If you lift heavy weights, and you also use a ketogenic diet, Luis is the oracle of evidence-based information. We pick his brain here.