Dr. Giles Yeo on Diet, and Weight Loss


This morning I enjoyed watching this presentation by Dr. Giles Yeo on understanding diet and weight loss. He highlights the principles around what is known as CICO, or Calories In, Calories Out, demonstrating how all diets for weight loss are based effectively on caloric deficit. At the same time, he insists that we should not exclusively ‘count calories’, but rather ‘count food’. He goes into a decent amount of detail about food labeling, the history of the Atwater System, and then describes a more modern scientific view on how to effectively achieve weight loss.

He quite charmingly describes the decades of work in the late 19th century of Atwater, who through a considerable amount of toil, determined the caloric value of macronutrients: carbohydrates, proteins, and fats. Yeo then explains the metabolic cost of digesting the various macronutrients and the process called ‘adaptive’ or ‘diet induced’ thermogenesis. That is to say, the calories we see on the label of a product are derived from the Atwater System which specify an approximate number of calories per gram of protein, fat, or carbohydrate…however, each of which will incur a metabolic cost to access. So, for example protein generates 4 calories per gram, at a cost of around 30% to extract the energy during the digestive process, making it 70% available. Calories from carbs and fats are closer to 90-95% available.

Finally he drives home the point that a diet relatively high in protein (16%+ of daily caloric intake) and unsoluable fiber, lead naturally to a caloric deficit. He achieves this by outlining a dozen or so modern diets, and grouping them according to their fundamental principles. Most fall into a ‘low carb’ classification, but each has it’s own focus and some have ‘more complicated back stories’. Diets mentioned include: Atkins, Keto, Carnivore, Paleo, Southwest, Dukan, Mediterranean, Gluten Free, Low Glycemic Index, Plant Based, Vegan, Alkaline, and Sirtfood. I will admit, a couple of these I’d never heard of. It is quite revealing to hear his quick take on how these diets are functionally very similar for most people, leading to a low carb, high fat, high protein balance for a daily caloric deficit.


You may also be interested in this discussion regarding where the weight goes when it’s lost!