||03-02-2009 06:55 AM
Prolonged adaptation to fat-rich diet and training.
Prolonged adaptation to fat-rich diet and training; effects on body fat stores and insulin resistance in man.
OBJECTIVE: To investigate the effect of prolonged adaptation to training and fat- or carbohydrate-rich diet on body composition and insulin resistance.
DESIGN: Longitudinal study. Of three groups two consumed a fat-rich diet, of which one performed regular training (FAT-Train, n=17) and the other maintained normal habitual activity (Fat-Control, n=8). The third group trained and consumed a carbohydrate-rich diet (CHO-Train, n=16).
SUBJECTS: Forty-one untrained, healthy male subjects.
MEASUREMENTS: Before and after 7 weeks body composition was estimated from skinfold measurements. At rest the respiratory exchange ratio (RER) was determined by the Douglas bag technique. Glycogen was determined in m vastus lateralis and concentrations of insulin and triacylglycerol in serum and glucose, fatty acid and beta-hydroxy-butyrate in plasma was measured. The insulin resistance index was calculated from fasting plasma insulin and glucose values.
RESULTS: Across the 7 weeks body weight was reduced (1.3▒0.3%) in all three groups, however body fat mass was decreased only in the CHO-Train (13%) and maintained in the two FAT-groups. RER at rest was similarly decreased (5%) in the three groups. Plasma insulin tended to decrease (16%) in CHO-Train (P=0.065) and remained unchanged in the two FAT-groups. In contrast plasma glucose (4.6▒0.1 mmol/l) and plasma FA (453▒27 Ámol/l) remained unchanged across the 7 weeks. The calculated insulin resistance index HOMA-Rmod was significantly decreased by 19% in CHO-train but remained unchanged in both of the FAT-groups, whereas the calculated insulin secretion index HOMA-mod was unchanged in all three groups.
CONCLUSION: In the present study we demonstrate that despite of a mild energy deficit body fat mass was maintained after prolonged adaptation to fat-rich diet both when normal physical activity was maintained and when training was performed. In contrast a significant decrease in fat mass was observed when carbohydrate-rich diet and training was combined. Furthermore we observed that the insulin resistance index was significantly decreased only when training was combined with a carbohydrate-rich diet.
||03-02-2009 08:06 AM
Of course... we have the nice fact of using LSD running as the exercise...
During the whole period physical training was performed four times a week. Each training session lasted between 60 and 75 min, and exercise intensity, which was carefully controlled, was varied from 50 to 85% of maximal oxygen uptake. The training program consisted of four different protocols with exercise intervals varying in length and duration interspersed with breaks of active recovery. Training intensity was adjusted to changes in maximal oxygen uptake measured after 3.5 weeks of the training period. At every training session heart rate was monitored with a heart rate recorder and frequently pulmonary oxygen uptake was measured and the training intensity controlled directly.
The other thing I am concerned with is that if people have not been on high fat or low fat diets BEFORE the training (most people as you know are on low fat before) the adaptation period of 1-3 weeks is going to negatively affect both their workouts and body composition. I don't see anywhere where this is taken into account.
In any case, it's gonna depend on genetics what is optimal for people so... this study really doesn't matter much when it comes to the individual, heh. Actually, most of the nutrition studies are like this ironically.
||03-02-2009 12:23 PM
Good catch Steven. I read the excerpt and thought.. "what? whats going on here..."
I stayed about the same for about a month as far as BF% on high fat/low carb diet, and then it started falling off after that, and ive maintained it since. So, 7 weeks dosent seem so 'prolonged'.
Thats interesting though. When I was running, I was on a very high carb, low fat/low protein diet, and I expereinced exactly those results. But, my muscle mass also experienced similar results.
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