|If you stick to the information in the abstract it sounds like a "low carb" diet intervention. Don't be fooled!|
The statement that they were evaluating the "functionality of an optimal gradual weight reduction (GWR) diet with high protein and low carbohydrate (CHO) to optimize jumping and sprint running performance while maintaining fat-free mass (FFM)," (Hovinen. 2015) is however, as the following elaborations, graphs and stats are about to show, grossly misleading, because what they really did was to evaluate the effects of a high carbohydrate, high protein, low fat diet... but we will get to that in a minute.
For their experiment, which lasted only 4 weeks, the scientist recruited 20- to 35-year-old national and international level Finnish track and field male athletes from jumping and short distance running events (e.g., 100–200 m). The participants had at least 5-year background in competitive athletics. All participants were advised to keep their training program consistent during WRP, which was also controlled and monitored for volume and intensity each week by the researchers and the athletes’ coaches
The athletes were randomly divided into 2 groups: high weight reduction (HWR; energy deficit 750 kcal/d; n = 8) and low weight reduction (LWR; energy deficit 300 kcal/day; n = 7).
"Nutritional intake before and during WRP is presented in Table 1. Significant differences between groups in nutritional intake during WRP were observed in fat (p <= 0.05), total energy intake (p <= 0.05), and CHO (p <= 0.05), which were lower in HWR than in LWR without differences in protein intake (~2.1 g·kg-1·d-1 in each situation) as planned.If you scrutinize the changes in the individual groups you will see that the relative reductions in protein, carbohydrate and fat intake were 0%, 15% and 14% for the LWR and 22% and 35% for the HWR group.
A significant time effect for energy intake and CHO per body mass (2 × 2 ANOVA) was observed (p <= 0.01), and although the total energy and CHO intake decreased in both groups during WRP, these changes were significant only in HWR (p <= 0.01)."
Table 1: Nutritional intake before and during weight reduction period. †Significant difference vs. before, p < 0.01; ‡Significant difference vs. LWR, p < 0.05 (Huovinen. 2015).
|Figure 1: Changes in body composition over the 4-week study period (Huovinen. 2015).|
This is not a classic low carb, let alone a ketogenic diet! Rather than just cutting back carbs, the track and field athletes in the study at hand reduced their already low fat intake from 72.27 g/day to 54.67 g/day which is lower than any of the low-carb advocated would ever go. Furthermore 46% of the total energy during the dieting phase come from carbs (23% from protein, the rest from fat). We are thus talking about an energy reduced high carbohydrate high protein diet, here where a higher fat intake was associated with lower fat loss (see figure in the bottom line).If we do the math for the relative contribution of the three large macronutrient groups, i.e. protein, fats and carbohydrates, you can easily see that the diet which produced allegedly impressive weight loss results is the diametrical opposite of a ketogenic diet.
|Figure 2: Macronutrient composition of the baseline and energy reduced diets (Huovinen. 2015).|
"There were no differences between the groups in serum hormone concentrations before and after WRP except cortisol, which was greater (p <= 0.05) in HWR than in LWR before WRP. Hormone concentrations did not differ significantly after the 4-week WRP" (Huovinen. 2015).So, cutting your fat intake to from low to marginal, obviously cannot be that bad for highly active individuals as some of the low carb enthusiasts claim. Take a parting look at the performance data in Figure 3 (values are calculated based on the body weight at the beginning and end of the study, respectively):
The latter, i.e. the reduction in pH and the correlating loss of bone mass, would yet probably not be compensated by an increase in fat intake. A more effective approach that has been shown to protect the bone mass in women on high protein diet is the ingestion of potassium or sodium bicarbonate (Lutz. 1984; Sebastian. 1994).
- Huovinen, H. et al. "Body Composition and Power Performance Improved After Weight Reduction in Male Athletes Without Hampering Hormonal Balance." Journal of Strength & Conditioning Research: January 2015 - Volume 29 - Issue 1 - p 29–36.
- Lutz, Josephine. "Calcium balance and acid-base status of women as affected by increased protein intake and by sodium bicarbonate ingestion." The American journal of clinical nutrition 39.2 (1984): 281-288.
- Sebastian, Anthony, et al. "Improved mineral balance and skeletal metabolism in postmenopausal women treated with potassium bicarbonate." New England Journal of Medicine 330.25 (1994): 1776-1781.