Fat
A macronutrient covering fats and oils, a concentrated source of energy, a component of cell membranes and a carrier of fat-soluble vitamins, long unfairly demonised.
Fat is the most energy-dense macronutrient (9 kcal/g against 4 for carbohydrate and protein). It includes fatty acids (saturated, mono- and polyunsaturated, trans), cholesterol and phospholipids.
Vital roles:
- Major energy reserve
- Forms the membranes of every cell
- Carries the fat-soluble vitamins (A, D, E, K): without fat, you do not absorb them
- Precursor of hormones (steroids) and signalling molecules
- Thermal insulation and protection of the organs
The original angle (the great rehabilitation): fat was wrongly demonised from the 1980s to the 2000s (“fat makes you fat and clogs your arteries”). This war on fat had a perverse effect: industry replaced fat with sugar in “light” products, paradoxically contributing to the obesity and diabetes epidemic.
Modern science has added nuance:
- Not all fats are equal (industrial trans fats are harmful, mono- and polyunsaturated fats are beneficial, saturated fats are neutral to moderate depending on context)
- Dietary fat does not mechanically “clog” the arteries: it is more complicated (inflammation, oxidation, sugars)
- “Low-fat” diets are not superior; the Mediterranean diet (rich in good fats) is among the healthiest
What really matters:
- Favour: monounsaturated fats (olive oil, avocado), omega-3 (oily fish, walnuts), fats from whole foods
- Moderate: saturated fats (depending on context and source)
- Avoid: industrial trans fats, oxidised refined oils, fats from ultra-processed foods
The “low-fat” trap: a product labelled “reduced fat” is often stuffed with sugar to make up for the taste. Reading labels remains essential: a plain whole-milk yoghurt beats a sweetened, flavoured 0% yoghurt.