The american heart association suggests that 8-10 percent of daily calories should come from polyunsaturated fats, and there is evidence that eating more polyunsaturated fatรขโ‚ฌup to 15 percent of รขโ‚ฌยฆ In nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such compounds, most commonly those that occur in living beings or in food. Learn what dietary fats do for the body and how much fat is recommended per day.