Despite intensive research, the causes of the obesity epidemic remain incompletely understood and conventional calorie-restricted diets continue to lack long-term efficacy. According to the carbohydrate-insulin model (CIM) of obesity, recent increases in the consumption of processed, high–glycemic-load carbohydrates produce hormonal changes that promote calorie deposition in adipose tissue, exacerbate hunger, and lower energy expenditure. Basic and genetic research provides mechanistic evidence in support of the CIM. In animals, dietary composition has been clearly demonstrated to affect metabolism and body composition, independently of calorie intake, consistent with CIM predictions. Meta-analyses of behavioral trials report greater weight loss with reduced-glycemic load vs low-fat diets, though these studies characteristically suffer from poor long-term compliance. Feeding studies have lacked the rigor and duration to test the CIM, but the longest such studies tend to show metabolic advantages for low-glycemic load vs low-fat diets. Beyond the type and amount of carbohydrate consumed, the CIM provides a conceptual framework for understanding how many dietary and nondietary exposures might alter hormones, metabolism, and adipocyte biology in ways that could predispose to obesity. Pending definitive studies, the principles of a low-glycemic load diet offer a practical alternative to the conventional focus on dietary fat and calorie restriction.
https://doi.org/10.1001/jamainternmed.2018.2933
Full Paper here
Notes:
rates of obesity remain intractably high despite intensive focus on reducing calorie intake (eat less) and increasing calorie expenditure (move more), with major implications to well-being, life-expectancy, and health care costs.
this model considers fat cells as central to the etiology of obesity, not passive storage sites of calorie excess.
Insulin decreases the circulating concentration of all major metabolic fuels by stimulating glucose uptake into tissues, suppressing release of fatty acids from adipose tissue, inhibiting production of ketones in the liver, and promoting fat and glycogen deposition.
Insulin is a super hormone, when its elevated the body stops feeding itself and stores everything.
inadequate insulin treatment of type 1 diabetes and drugs that inhibit insulin secretion cause weight loss.
Dietary fat has little direct effect on insulin, providing a theoretical basis for the efficacy of high-fat diets.
the carbohydrate-insulin model of obesity (CIM) proposes that a high-carbohydrate diet—including large amounts of refined starchy foods and sugar, as commonly consumed in the lowfat diet era—produces postprandial hyperinsulinemia, promotes deposition of calories in fat cells instead of oxidation in lean tissues, and thereby predisposes to weight gain through increased hunger, slowing metabolic rate, or both
Carbs/Sugars drive weight gain and hunger, its a vicious cycle.
calorie restriction can be viewed as symptomatic treatment, destined to fail for most people in the modern food environment. Low-calorie, low-fat diets may actually exacerbate the underlying metabolic problem by further restricting energy available in the blood—triggering the starvation response comprised of rising hunger, falling metabolic rate, and elevated stress hormone levels
People eating a high carb diet are always hungry because all of their internal stored energy (fat) is unavailable to them. They are always starving even though they have plenty of fat.
Even when calorie-restricted to prevent excessive weight gain, insulin-treated animals still developed excessive body fat consistent with a prediction of the CIM regarding fuel partitioning
CICO / Eat Less Move More - Would say that the food doesnt matter, but in animals adding insulin without changing the diet causes weight gain! This disproves the simplistic CICO advice of weight loss.
calorie restriction to prevent excessive weight gain in animals on a high-GI diet did not prevent excessive adiposity or the associated cardiometabolic risk factors
If the insulin is elevated (carbs/sugar in the diet) even calorie restriction does not prevent obesity in animals
The importance of this cannot be understated, humans are amazing hormonal machines. Hormones control every aspect of our biology. The hormonal insulin model has dramatic application to human health and specifically obesity / insulin resistance / metabolic health.
TLDR: Insulin is the cause of almost all obesity you see. Carbohydrates drive blood sugar, blood sugar drives insulin, insulin drives weight gain. As a good example - T1Ds who don’t take their insulin wont gain weight, no matter how much they eat.
I think this leads people to draw the wrong conclusions about activity and weight. They are correlated, but most people think active people have less weight.
But really it’s much more likely that certain people’s hormones only tell their body to store a little fat. If they eat more than is needed for that, the body must burn those calories, so they are then more active.
But people so often think that they need to exercise if they need to lose weight. (Additionally, this may be counterproductive because if your hormones needed to store fat, and you’ve burned the calories already, you’re going to be more hungry, and trying to resist that is just torture.)
Some populations are very sensitive to carbohydrates, native americans for example. So there is a spectrum of carbohydrate tolerance out there.
But people so often think that they need to exercise if they need to lose weight. (Additionally, this may be counterproductive because if your hormones needed to store fat, and you’ve burned the calories already, you’re going to be more hungry, and trying to resist that is just torture.)
Exercise is healthy, but not a great way to lose weight by itself. But exercise is a good adjunct to a weight loss program. The hormone insulin is driven by diet, if the diet is clean and insulin is low, exercise wont change that. In fact when people are doing a ketogenic diet, when they exercise, they burn fat not sugar, so they don’t need to eat more food (if they are overweight) and they don’t feel tortured.
Yes, those are great clarifications
