An interesting interview selling his new book:
" Can you explain why you feel calorie-counting is a flawed approach to weight loss?
There was an American chemist in the 19th century called Wilbur Olin Atwater who calculated the calorie numbers for different foods, by working out the total energy intake you get from them. But his calculations never took into account the energy it takes our cells to metabolise food in order to use it. This is important. It’s why for example a calorie of protein makes you feel fuller than a calorie of fat, because protein is more complex to metabolise. For every 100 calories of protein you eat, you only ever absorb 70.
So we need to consider the type of food we’re eating, rather than fixating purely on the calorie content. You could be aiming to eat 800 calories a day, but how much energy your body actually absorbs will depend on whether you’re eating sugar, celery, or steak."