This one is actually true! There was a brilliant piece on this in New Scientist magazine a few years ago. The calorific value of food does nor include the energy needed to eat or metabolise it but you would need to eat a ridiculous amount of celery to negate the effect of, say, a chocolate digestive, so in theory yes, but in practice, no. Cabbage soup does not burn fat as you say Bethannie. But it does help you lose weight if all you eat is cabbage soup, as it contains few calories and lots of fibre. Also, you tend to eat less of it as well, as the diet progresses, as it's so boring!