mRNA expression of pparα (A), ucp3 (B), cte1 (C), mte1 (D), pdhk4 (E) and glut4 (F) in the soleus muscle of rats fed on low fat, Western or high fat diet in the acute (AT), short (ST), intermediate (IT) and long term (LT). Values are means±S.E.M. for 14–24 independent experiments per group. Closed squares (■) represent low fat diet-fed rats, closed circles (●) represent Western diet-fed rats and closed triangles (▲) represent high fat diet-fed rats. *, P<0.05, **, P<0.01 and ***, P<0.001 compared with low fat diet at the same age. $, P<0.05, $$, P<0.01 and $$$, P<0.001 compared with Western diet at the same age.