High fat diet and endurance training have opposite effects on heat production in brown and white fat and influence overall energy use in rats

A high fat diet increased thermogenic capacity in brown adipose tissue but exercise reduced it.

• A high fat diet enhanced the thermogenic capacity of brown adipose tissues in sedentary rats.
• Exercise training suppressed the thermogenic capacity of classical brown adipose tissue.
• Exercise led to browning of subcutaneous white adipose tissue, which was inhibited by a high fat diet.
• Endurance training increased the local content of FNDC5 in subcutaneous white adipose tissue but did not affect FNDC5 levels in skeletal muscle or circulating irisin.
• Despite reduced thermogenic capacity in classical brown adipose tissue, exercise increased whole-body energy expenditure during the dark cycle.
• Browning of subcutaneous white adipose tissue may compensate for changes in thermogenic capacity and help regulate overall energy expenditure.

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