Nutritionist and personal trainer Luke Hanna tells Harry Bullmore six things that most people should do differently when it comes to nutrition F at loss is a common fitness goal. It’s also a more complex topic than many would have you believe. The laws of thermodynamics apply; if you burn more calories than you consume, you will achieve a calorie deficit and lose weight. But there is a matrix of individualised factors such as genetics, appetite and environment that make this difficult for many.