Dr. Fung’s Newsletter

Photo by Jezebel Rose on Unsplash How do we know when to stop eating? It’s not because we get to a certain number of calories. We don’t naturally stop eating because we hit 500 or 800 or 1000 calories, because for all of human history (several million years), we don’t know exactly how many calories we ate. Yet despite this, until about the late 1970s humans largely avoided both starvation and obesity.

Photo by Andrea Leon on Unsplash Focusing on calories does not lead to weight loss.Many ‘experts’ focus myopically on calories with the mistaken belief that ‘it’s all about calories’ because the energy balance equation says: This can be rewritten as: This is technically true, just as Alcohol In > Alcohol Out leads to drunkenness/ alcoholism. However, stating the solution to worldwide alcoholism is just to drink less alcohol, or metabolize more alcohol is ridiculous.

Photo by Davies Designs Studio on Unsplash The food matrix is the physical domain that contains or interacts with the specific constituents of the food — eg. the macronutrients — carbs, proteins, fats, and micronutrients — vitamins, minerals etc.

Virtually all ‘obesity experts’ claim that weight gain is all about calories, and this widely believed misconception has led to a worldwide obesity epidemic.The belief that 100 calories of cookies have the same fattening effect as 100 calories of salmon is simply not correct. Those two 100 calorie portions of foods have widely divergent hormonal effects, and we gain or lose weight based on our hormones.

The hormone insulin is one of the main drivers of obesity.While the amount of carbohydrates plays a big role in insulin effect, (which is why low carb diets can be very effective), it is not the ONLY factor affecting insulin secretion.

Photo by Mae Mu on Unsplash Understanding obesity as simply calories in, calories out is not useful at all because it doesn’t try to understand WHY calories in> calories out — ie. ultra processed foods, food addictions, mindless eating, depression, poor habits, lack of eating schedules.If people are addicted to food, and therefore calories in> calories out, then we need to treat the addiction, not just tell people to ‘eat fewer calories’. It’s 100% not useful.

The ‘gold standard’ for weight loss strategies is aptly named “Eat Less, Move More” based on the Calories In, Calories Out notion. Because Body Fat = Calories In — Calories Out, nutritional authorities say that to lose Body Fat, you need to either reduce Calories In (ie. Eat Less) or increase Calories Out (ie. Move More). This advice is everywhere you look. The US government (nutrition.gov) tells you this in no uncertain terms. The American Heart Association provides virtually identical advice.

The human body stores energy in two main forms – 1. Glucose (sugar) 2. Fat (body fat). Glucose is stored in the liver in long chains known as glycogen. Once the glycogen storage system is full, the body can turn excess glucose into fat in the process known as de novo lipogenesis. The body can also use two main forms of stored energy when food is not available — glucose and fat. This makes sense because it corresponds exactly to the way it’s stored.

Weight gain is often considered a problem with ‘overeating’. So why do we overeat? Not because we choose to, but because we’re hungry. Therefore, if we consider the problem at a deeper level, we must control hunger and satiety, not calories, because it is hunger that drives eating behavior. Satiety measures how full we feel after eating, where hunger is what drives our desire to eat. Why are we hungry?

Hunger (which is a hormonally mediated state) often leads to eating more calories which leads to weight gain. This does not break any ‘laws of thermodynamics’. Instead, it simply tries to understand the problem of overeating at a deeper level, getting the root causes. Trying to reduce calories without addressing this hunger is doomed to fail. Just as trying to cure depression by just telling somebody to ‘cheer up’ is useless. Or trying to cure alcoholism by telling somebody to just ‘drink less’.