Comparison of Nutrient Adequacy and Chronic Disease Risk Factors Among Those Following a Ketogenic-like vs. Mediterranean-like Diet: A Post-Hoc Analysis of Participants in the DIETFITS Weight Loss Diet Study

Introduction
The typical American diet is full of excess calories, high sodium intake, refined carbohydrates, and a surplus of sugar. Chronic diseases directly associated with diet are on the rise and, more than ever before, innovative diet approaches are called for. Growing evidence points to the potential health advantages for a diet higher in fat and lower in carbohydrates. The Mediterranean diet is becoming a popular lifestyle choice with broad support from public health professionals. A more extreme low-carbohydrate/high-fat alternative is the ketogenic diet.
Objective
Using data from the DIETFITS trial, a weight loss diet study, a post hoc analysis was performed to examine the nutrient profiles and chronic disease risk factors of two diet subgroups selected from the DIETFITS Study, using data collected at baseline and 3 months. Examining this relationship may provide a better understanding of the effects these diets have.
Design
The DIETFITS study was an analysis of a 12-month weight loss diet intervention that investigated within group differences of biological variables. This analysis looked at the following anthropometric and metabolic risk factors (weight, waist measurement, BMI, fasting blood cholesterol, glucose, and insulin, and blood pressure) as well as vitamins (vitamin A, thiamin, riboflavin, niacin, vitamin B6, folate, vitamin B12, vitamin C, vitamin D, vitamin E, vitamin K) and minerals (calcium, iron, magnesium, phosphorus, potassium, selenium, sodium, zinc).
Participants
Generally healthy, non-diabetic adults aged 18-50 years with a BMI from 28-40 kg/m2. Average age of the selected participants (n=68) was 41 years, with an almost equal split between male and female participants (48% male, 52% female).
Methods
To compare two low-carbohydrate/high-fat diets, two groups were selected using diet-specific selection criteria. A ketogenic-like group was compared to a Mediterranean-like group at baseline and 3-months across many anthropometric and metabolic variables as well as nutrient profile. Significance was tested using unpaired t-tests.
Results
Significant improvement was found within both the ketogenic-like and Mediterranean-like groups from baseline to 3-month in many anthropometric and metabolic risk factors. The nutrient profile changes from baseline to 3-months rarely were cause for inadequacy. Between group significance was found in triglycerides, thiamin, and selenium favoring the ketogenic-like group, and potassium, which favored the Mediterranean-like group.
Conclusion
With the exception of the favorable impact on blood triglycerides, this analysis did not find significant improvements in risk factors for the ketogenic-like group compared to the Mediterranean-like group. In the context of trying to choose a dietary modification that is lower in carbohydrate and higher in fat than has been the traditional public health approach to an overall healthy diet, these findings support choosing a Mediterranean diet, rather than a ketogenic diet given the considerable added restrictions of the latter.