Combined effects of endurance training and dietary unsaturated fatty acids on physical performance, fat oxidation and insulin sensitivity

• Published in: British journal of nutrition 2010-04, Vol.103 (8), p.1151-1159
• Main Authors: Boss, Andreas, Lecoultre, Virgile, Ruffieux, Christiane, Tappy, Luc, Schneiter, Philippe
• Format: Article
• Language: English
• Subjects: Adult; athletic performance; Biological and medical sciences; Blood Glucose - metabolism; Body Composition; Calorimetry; Calorimetry, Indirect - methods; Carbohydrates; Diet; dietary fat; exercise; Exercise - physiology; Exercise Test; experimental diets; Fat oxidation; Fatty acids; Fatty Acids, Nonesterified - blood; Fatty Acids, Unsaturated - pharmacology; Feeding. Feeding behavior; fish oils; Fundamental and applied biological sciences. Psychology; Human and Clinical Nutrition; human nutrition; Human performance; Humans; Ingestion; Insulin; Insulin - blood; Insulin resistance; Insulin sensitivity; Lactates - blood; lipid peroxidation; Lipids - physiology; Male; men; Oils & fats; Olive oil; omega-3 fatty acids; omega-6 fatty acids; Oxidation; Oxidation-Reduction; oxygen consumption; Oxygen Consumption - drug effects; Physical Endurance - drug effects; Physical performance; Sports training; synergism; Training; Unsaturated fatty acids; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Young Adult; young adults
• ISSN: 0007-1145; 1475-2662
• DOI: 10.1017/S000711450999287X

Endurance training improves exercise performance and insulin sensitivity, and these effects may be in part mediated by an enhanced fat oxidation. Since n-3 and n-9 unsaturated fatty acids may also increase fat oxidation, we hypothesised that a diet enriched in these fatty acids may enhance the effects of endurance training on exercise performance, insulin sensitivity and fat oxidation. To assess this hypothesis, sixteen normal-weight sedentary male subjects were randomly assigned to an isoenergetic diet enriched with fish and olive oils (unsaturated fatty acid group (UFA): 52 % carbohydrates, 34 % fat (12 % SFA, 12 % MUFA, 5 % PUFA), 14 % protein), or a control diet (control group (CON): 62 % carbohydrates, 24 % fat (12 % SFA, 6 % MUFA, 2 % PUFA), 14 % protein) and underwent a 10 d gradual endurance training protocol. Exercise performance was evaluated by measuring VO2max and the time to exhaustion during a cycling exercise at 80 % VO2max; glucose homeostasis was assessed after ingestion of a test meal. Fat oxidation was assessed by indirect calorimetry at rest and during an exercise at 50 % VO2max. Training significantly increased time to exhaustion, but not VO2max, and lowered incremental insulin area under the curve after the test meal, indicating improved insulin sensitivity. Those effects were, however, of similar magnitude in UFA and CON. Fat oxidation tended to increase in UFA, but not in CON. This difference was, however, not significant. It is concluded that a diet enriched with fish- and olive oil does not substantially enhance the effects of a short-term endurance training protocol in healthy young subjects.