The word "isocaloric" means that something has the same amount of calories as something else. It refers to situations where two things, like meals or diets, have an equal number of calories. Full definition
Methods: Adult C57Bl / 6 mice were subjected to isocaloric high - fat / high - sucrose diets (HFD), enriched in either saturated or monounsaturated fat, or a control low - fat diet (LFD). (molecularmetabolism.com)
This is a controversial idea, and there are perceptions that variable weight loss with isocaloric diets would somehow violate the laws of thermodynamics and that there must be some experimental error. (academic.oup.com)
Comparison of isocaloric very low carbohydrate / high saturated fat and high carbohydrate / low saturated fat diets on body composition and cardiovascular risk. (totalwellbeingdiet.com)