|Unfortunately, this is not a photo of the "ketogenic diet" meals the subjects were served in exactly 2 out of 24 months of the study... ah, and the various supple-ments they were taking to make up for nutrional deficits are also missing.|
Unfortunately, this is where reason #2 comes into play: Not too long ago you would probably have had problems to get funding and/or to even get past the ethics committee of your institution with a study in which overweight or obese subjects were supposed to be exposed to a "high fat" and or "high protein" diet that could "jeopardize their health".
Over the past decade, however, the number of low carb dieters and researchers who back the notion of "eating more fat to lose fat" has been growing continuously. You cannot say that the tides are turning, yet, but the existing experimental evidence which shows that low carb or ketogenic diets are effective, at least in the short to medium term, as a tool to fight obesity (Bueno. 2013) is convincing enough to get permission and financing (in this case by a Spanish protein supplement producer who funded the study and supplied the protein powder used in the study) for long-term keto studies.
Against that background, the latest study by Basilio Moreno et al. (2016) would not be an exception to the role but still one out of a selected few studies that assessed the effects of a ketogenic diet on glycemia, lipidemia and body composition (esp. visceral fat) over 2 years and compared the outcomes to both, a non-dieting control and a regular low calorie control group (LC), the scientists describe as follows (Moreno. 2016):
- Low-calorie control (LC) - The standard LC diet was an equilibrated diet that had a caloric value 10 % below the total metabolic expenditure of each individual. The total metabolic expenditure was calculated from the basal metabolic expenditure (based on the formula FAO/WHO/UN) multiplied by the coefficient of activity, which was calculated according to the physical activity of each participant. The calories provided to this group ranged between 1400 and 1800 kcal/day. The ratio of macronutrients provided was 45–55 % carbohydrates, 15–25 % proteins, and 25–35 % fat in addition to a recommended intake of 20–40 g/day of fiber in the form of vegetables and fruits. A ratio exchange model was followed
- Very low-calorie ketogenic diet (VLCK) - The VLCK diet group followed a diet according to a commercial weight loss program (Pronokal method) based on a high biological value protein preparations diet and natural foods. Each protein preparation contained 15 g of protein, 4 g of carbohydrates, and 3 g of fat, and provided 90–100 kcal. This method has three stages: the active stage, the re-education stage, and the maintenance stage (Fig. 1). The active stage consists of a very low-calorie diet (600–800 kcal/day) that is low in carbohydrates (< 50 g daily from vegetables) and lipids (only 10 g of olive oil per day). The amount of high biological value proteins ranges between 0.8 and 1.2 g per each kg of ideal body weight, to ensure that it meets minimal body requirements and prevents the loss of lean mass. This method produces three ketogenic phases. In phase 1, the patients eat high biological value protein preparations five times a day, and vegetables with a low glycemic index. In phase 2, one of the protein servings is substituted with a natural protein (e.g., meat or fish) either at lunch or at dinner. In phase 3, a second serving of a low-fat natural protein replaces the second serving of a biological protein preparation.
In the re-education stage, the ketogenic phases were ended by the physician in charge of the patient based on the amount of weight lost, and a low-calorie diet was initiated. At this point, the patients underwent a progressive incorporation of different food groups and participated in a program of alimentary re-education to guarantee the long-term maintenance of the weight lost (Fig. 1). The maintenance stage, which lasted 2 years, consisted of an eating plan balanced in carbohydrates, protein, and fat. Depending on the individual, the calories consumed ranged between 1500 and 2000 kcal/day, and the target was to maintain the lost weight and promote a healthy lifestyle.
- VLCK - "cut rapid- and severely and try to maintain afterward"
- LC - "lose weight slowly & continuously w/ lifestyle change + minimal deficit"
|Figure 3: Lean body mass (LBM) and fat mass (FBM) loss in the two groups over time (Moreno. 2016).|
Still impressive? Ok. So how practically relevant is it if we all know that this diet is not sustainable and it takes only 14 months on a still very strict "balanced maintenance diet" to regain 10.3 kg of the 19.1kg (i.e. 54%) without regaining any of the previously lost lean body mass? I refuse to answer this question, but I think I have given you all the information that's necessary to answer it for yourselves.
- Bueno, Nassib Bezerra, et al. "Very-low-carbohydrate ketogenic diet v. low-fat diet for long-term weight loss: a meta-analysis of randomised controlled trials." British Journal of Nutrition 110.07 (2013): 1178-1187.
- Moreno, Basilio, et al. "Obesity treatment by very low-calorie-ketogenic diet at two years: reduction in visceral fat and on the burden of disease." Endocrine (2016): 1-10.