A recent study in the journal Nature found that mice who were fed a breakfast in which 45 percent of the calories came from fat tended to burn more body fat over the next 24 hours than those who ate a meal that was only 20 percent fat. This is early research—it needs to be repeated in humans—but mono and polyunsaturated fats like those found in avocados and nuts do have plenty of health benefits when you eat them in moderation.
This may explain why the fat-burning effects of eating more protein were confirmed in a study published in the American Journal of Physiology. One group was fed a high-protein diet (just over 1 gram per pound of body weight per day) while the second group consumed an amount closer to the lower recommendation of the RDA (recommended dietary allowance). The group eating the higher-protein diet burned the most fat.