Metabolic characteristics of keto-adapted ultra-endurance runners. FASTER (Fat Adapted Substrate use in Trained Elite Runners)
Overview: Twenty elite ultra-marathoners and ironman distance triathletes performed a maximal graded exercise test and a 180 min submaximal run at 64% VO2max on a treadmill to determine metabolic responses. One group habitually consumed a traditional high-carbohydrate (HC: n = 10, %carbohydrate:protein:fat = 59:14:25) diet, and the other a low-carbohydrate (LC; n = 10, 10:19:70) diet for an average of 20 months (range 9 to 36 months).
Results: Peak fat oxidation was 2.3-fold higher in the LC group (1.54 ± 0.18 vs 0.67 ± 0.14 g/min; P = 0.000) and it occurred at a higher percentage of VO2max (70.3 ± 6.3 vs 54.9 ± 7.8%; P = 0.000). Mean fat oxidation during submaximal exercise was 59% higher in the LC group (1.21 ± 0.02 vs 0.76 ± 0.11 g/min; P = 0.000) corresponding to a greater relative contribution of fat (88 ± 2 vs 56 ± 8%; P = 0.000). Despite these marked differences in fuel use between LC and HC athletes, there were no significant differences in resting muscle glycogen and the level of depletion after 180 min of running (− 64% from pre-exercise) and 120 min of recovery (− 36% from pre-exercise).
Conclusion: Compared to highly trained ultra-endurance athletes consuming an HC diet, long-term keto-adaptation results in extraordinarily high rates of fat oxidation, whereas muscle glycogen utilization and repletion patterns during and after a 3 hour run are similar.
Study By: Jeff S. Volek Daniel J. Freidenreich Catherine Saenz Laura J.Kunces Brent C.Creighton Jenna M.Bartley Patrick M.Davitt Colleen X.Munoz Jeffrey M.Anderson Carl M.Maresha Elaine C.Lee Mark D.Schuenke Giselle Aernia William J.Kraemer Stephen D.Phinney
Full Study Text: www.metabolismjournal.com/article/S0026-0495(15)00334-0/fulltext
A Low-Carb Diet is More Effective in Reducing Body Weight Than Healthy Eating in Both Diabetic and Non-Diabetic Subjects
Details: 13 diabetic and 13 non-diabetic individuals were randomized to a low-carb diet or a “healthy eating” diet that followed the Diabetes UK recommendations (a calorie restricted, low-fat diet). Study went on for 3 months.
Weight Loss: The low-carb group lost 6.9 kg (15.2 lbs), compared to 2.1 kg (4.6 lbs) in the low-fat group.
Conclusion: The low-carb group lost more weight (about 3 times as much). There was no difference in any other marker between groups.
Read more at Diabetic Medicine by way of Kris Gunnars, Authority Nutrition.
Details: 322 obese individuals were randomized to three diets: a low-carb diet, a calorie restricted low-fat diet and a calorie restricted Mediterranean diet. Study went on for 2 years.
Weight Loss: The low-carb group lost 4.7 kg (10.4 lbs), the low-fat group lost 2.9 kg (6.4 lbs) and the Mediterranean diet group lost 4.4 kg (9.7 lbs).
Conclusion: The low-carb group lost more weight than the low-fat group and had greater improvements in HDL cholesterol and triglycerides.
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New England Journal of Medicine by way of Kris Gunnars, Authority Nutrition.
Details: 40 subjects with elevated risk factors for cardiovascular disease were randomized to a low-carb or a low-fat diet for 12 weeks. Both groups were calorie restricted.
Weight Loss: The low-carb group lost 10.1 kg (22.3), while the low-fat group lost 5.2 kg (11.5 lbs).
Conclusion: The low-carb group lost almost twice the amount of weight as the low-fat group, despite eating the same amount of calories.
Read more at Lipids by way of Kris Gunnars, Authority Nutrition.
Comparison of Energy-Restricted Very Low-Carbohydrate and Low-Fat Diets on Weight Loss and Body Composition in Overweight Men and Women
Details: A randomized, crossover trial with 28 overweight/obese individuals. Study went on for 30 days (for women) and 50 days (for men) on each diet, that is a very low-carb diet and a low-fat diet. Both diets were calorie restricted.
Weight Loss: The low-carb group lost significantly more weight, especially the men. This was despite the fact that they ended up eating more calories than the low-fat group.
Conclusion: The low-carb group lost more weight. The men on the low-carb diet lost three times as much abdominal fat as the men on the low-fat diet.
Read more at Nutrition and Metabolism by way of Kris Gunnars, Authority Nutrition.
Randomized Trial Comparing a Very Low Carb Diet and a Calorie-Restricted Low Fat Diet in Healthy Women
Details: 53 healthy but obese females were randomized to either a low-fat diet, or a low-carb diet. Low-fat group was calorie restricted. The study went on for 6 months.
Weight Loss: The women in the low-carb group lost an average og 8.5 kg (18.7 lbs), while the low-fat group lost an average of 3.9 kg (8.6 lbs). The difference was statistically significant at 6 months.
Conclusion: The low-carb group lost more weight (2.2 times as much) and had significant reductions in blood triglycerides. HDL improved slightly in both groups.
Read more at The Journal of Clinical Endocrinology and Medicine by way of Kris Gunnars, Authority Nutrition.
Details: 132 individuals with severe obesity (mean BMI of 43) were randomized to either a low-fat or a low-carb diet. Many of the subjects had metabolic syndrome or type II diabetes. The low-fat dieters were calorie restricted. Study duration was 6 months.
Weight Loss: The low-carb group lost an average of 5.8 kg (12.8 lbs) while the low-fat group lost only 1.9 kg (4.2 lbs). The difference was statistically significant.
Conclusion: The low-carb group lost significantly more weight (about 3 times as much). There was also a statistically significant difference in several biomarkers:
Read more at the New England Journal of Medicine by way of Kris Gunnars, Authority Nutrition.