What is Metabolizable Energy? An Essential Guide to Usable Calories
                                
                                
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                                    4 min read                                
                            
                                According to nutritional studies, humans and animals lose up to 10-15% of total food energy through feces and urine. This unabsorbed portion is why the total energy content of food, measured through combustion, is not the same as the energy an organism can actually use, a value known as metabolizable energy.