Dr. Fung’s Newsletter

Photo by Todd Morris on Unsplash Our body controls the amount of body fat we carry like a thermostat (see Part 1). Obesity is the state of having the body fat thermostat set too high. They are the same thing. What causes obesity? This is the same question as — what controls the body fat thermostat? Most people think, incorrectly, that the answer is ‘Too many calories’. To this way of thinking, all calories, regardless of type, are equally fattening.

The amount of body fat we carry is regulated much like a thermostat (see The Body Fat Thermostat Part1). If you eat less, you’ll become more hungry (see Part2 — The Science, andPart 3 — Understanding Hunger), which will eventually make you want to eat more. If you white knuckle it and use all your willpower to force yourself to continue eating less despite the increased hunger, (driven by hormones), then your body will reduce the Calories Out so that Body Fat is maintained. (See Part 4).

The energy balance equation, which is always true says Energy Balance Equation If you don’t think about it too hard, it seems that to lose body fat, you only need to eat fewer calories or exercise more. That’s only been tried about a few million times and fails just about always. The reason is that Body Fat is regulated like a thermostat — as we discussed in Part 1.

Photo by Siegfried Poepperl on Unsplash In Part 1 of the Body Fat Thermostat, we discussed how body fat is highly regulated like a thermostat, and not merely left to the vagaries of how much we eat in a day. We considered the mechanisms for homeostasis, according to the Energy Balance Equation. Body Fat = Calories In Minus Calories Out Homeostasis of the Body Set Weight (BSW) means that if you lose weight, your body will try to regain that weight.

My last article, The Body’s Fat Thermostat — Part 1, discussed the concept of homeostasis and how body fat is regulated like a thermostat rather than simply the end product of Calories In — Calories Out. The level set by the thermostat is determined by multiple hormones (like most everything else in our body), rather than the number of calories we eat.

Photo by Jon Ly on Unsplash How much body fat we carry is controlled through a homeostatic mechanism and is not simply the result of how many calories we eat and burn in a day. Many ‘experts’ believe that hormones have little role in determining the amount of body fat we carry, and that is really is just as simple as the calories we eat versus the amount of exercise we do. Many decades of research shows that this is false.

Photo by Iñigo De la Maza on Unsplash When talking about nutrition for weight loss, we often focus exclusively a single variable of foods — such as: · Calories (Low Calorie!) · Carbs (Low Carb!) · Fats (Low Fat!) · Fiber (High Fiber!) · Protein (High Protein!) Weight Gain Model Such reductionist thinking on diets usually fails (See my YouTube video — Why Calorie Deficits don’t work). There are many intermediate steps between the foods we eat and the weight we gain.

The GLP-1 agonist drugs, Ozempic and Mounjaro cause significant and sustained weight loss by affecting the incretin hormones. (See my article — What Ozempic teaches us about Weight Loss) So understanding these systems and what foods affect them can lead us to rational food choices to maximize weight Incretins are hormones secreted in the intestines which play several major roles in food intake: 1. Increases insulin secretion in the pancreas to aid digestion 2.

Photo by Brian McGowan on Unsplash Starches are polysaccharides (long chains of sugar molecules) arranged into two main structures — amylopectin and amylose. Most starches in the human diet (wheat, rice, oats etc.) are about 70% amylopectin and 30% amylose and are digested at varying rates, with differing rates of blood glucose increase and insulin release, with all its weight loss implications.

Photo by ANTIPOLYGON YOUTUBE on Unsplash Most Americans (50–85%) don’t get the recommended daily intake of magnesium, according to the National Academy of Science leading to magnesium deficiency. This may contribute to diseases such as high blood pressure, diabetes, and neurologic disease. A 2013 meta-analysis finds that lower dietary magnesium intake is correlated to higher risk of heart disease. Eating a events.