Category: Energy science

A gram of fat is famously known to contain 9 calories, more than double the energy of carbohydrates or protein. However, the human body's metabolic efficiency is just one aspect of energy density, and when considering the broader scientific landscape, fat is far from the most potent energy source available.

Scientific studies and nutritional guidelines confirm that lipids, specifically fats, yield approximately 9 kilocalories per gram, establishing them as the most energy-dense macronutrient. This makes fat the molecule that provides the most energy per gram for living organisms, significantly outperforming carbohydrates and proteins in terms of energy storage efficiency.

The theoretical annihilation of matter and antimatter produces the most energy per gram by far, based on Einstein's famous equation $E=mc^2$. A single gram of antimatter, when reacting with a gram of ordinary matter, would release an immense amount of energy, fundamentally changing mass into pure energy.