It's a major debate of the nutrition world that's rumbled on for years: What's healthier - full fat, or semi-skimmed milk? In comparison, a small glass of semi-skimmed contains just over 2g of saturated fat and 100 calories. 'I would never not recommend full fat milk or yoghurt,' she says. ‘The fat contains all the beneficial vitamins - A, D, E and K, which the low fat versions don’t have,’ Kingswell adds. However, skimmed milk contains less vitamin D than full-fat milk, which helps the body absorb the crucial nutrient.