Interaction between dietary lipids and physical inactivity on insulin sensitivity and on intramyocellular lipids in healthy men.
OBJECTIVE
To assess the effect of a possible interaction between dietary fat and physical inactivity on whole-body insulin sensitivity and intramyocellular lipids (IMCLs).


METHODS
Eight healthy male volunteers were studied on two occasions. After 2 days of an equilibrated diet and moderate physical activity, participants remained inactive (bed rest) for 60 h and consumed either a high-saturated fat (45% fat, of which approximately 60% was saturated fat [BR-HF]) or a high-carbohydrate (70% carbohydrate [BR-HCHO]) diet. To evaluate the effect of a high-fat diet alone, six of the eight volunteers were restudied after a 2-day equilibrated diet followed by 60 h on a high-saturated fat diet and controlled physical activity (PA-HF). Insulin sensitivity was measured by hyperinsulinemic-euglycemic clamp and IMCL concentrations by (1)H-magnetic resonance spectroscopy.


RESULTS
Insulin-mediated glucose disposal was decreased by BR-HF condition (-24 +/- 6%, P < 0.05) but did not change with BR-HCHO (+19 +/- 10%, NS). BR-HF and BR-HCHO increased IMCL levels (+32 +/- 7%, P < 0.05 and +17 +/- 8%, P < 0.0011, respectively). Although the increase in IMCL levels with PA-HF (+31 +/- 19%, P = 0.12) was similar to that during BR-HF, insulin-mediated glucose disposal (-7 +/- 9%, NS) was not decreased.


CONCLUSIONS
These data indicate that physical inactivity and a high-saturated fat diet may interact to reduce whole-body insulin sensitivity. IMCL content was influenced by dietary lipid and physical inactivity but was not directly associated with insulin resistance.
Stettler
Rodrigue
R
Département de Physiologie, 7 rue du Bugnon, 1005 Lausanne, Switzerland.
Ith
Michael
M
Acheson
Kevin J
KJ
Décombaz
Jacques
J
Boesch
Chris
C
Tappy
Luc
L
Binnert
Christophe
C
D000328:Adult; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism*; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D015309:Glucose Clamp Technique; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D008019:Life Style; D008297:Male; D009043:Motor Activity; D010809:Physical Fitness
D001786:Blood Glucose; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D007328:Insulin