Some “experts” believe that insulin is a harmful hormone that leads to weight gain and type 2 diabetes. They claim that consuming carbohydrates triggers insulin production, causing adverse effects on our bodies. But do these claims hold up? Is it logical for our bodies to have a harmful response to carbohydrate intake? Let’s explore this topic further.
Insulin is a hormone produced by the pancreas that regulates blood sugar levels alongside glucagon and other hormones. It is primarily anabolic, aiding in building molecules and tissues, but it also has some catabolic properties for energy production.
When active, insulin plays a vital role in managing nutrient distribution in the body. It directs nutrients into the liver, fat, and muscle, helping to clear them from the blood. Insulin also influences metabolism by favoring carbohydrates as the primary fuel source, reducing the use of fats and proteins for energy. Insulin shuttles nutrients from the bloodstream into fat cells, helping to build more fat molecules, but it also shuttles nutrients into muscle cells to help build muscles.
The Carbohydrate-Insulin Model (CIM) of obesity is a theory that links carbohydrate intake with insulin levels and weight gain. According to the model, consuming carbs raises insulin levels to manage blood sugar. Still, it also inhibits the release of fatty acids from fat tissue and shuttles sugar and fat into fat cells, potentially causing weight gain.
Supporters of the CIM argue that high carbohydrate intake leads to high insulin levels, which can trap fat in cells and increase body fat. They also believe that low-carb diets promote weight loss without the need for calorie counting, reinforcing that controlling insulin levels through carbohydrate intake is crucial in managing body weight.
There is some theoretical support for the idea that insulin triggers lipogenesis and fat creation in the body. The popularity of the insulin hypothesis grew with the publication of Gary Taubes’s book Good Calories, Bad Calories, which positioned insulin as a central factor in controlling fat and body weight. Critics, however, argue that these claims oversimplify the complexity of metabolism and rely on myths and pseudoscience.
Insulin shuttles nutrients from the bloodstream into fat cells, helping to build more fat molecules, and it also shuttles nutrients into muscle cells to help build muscle. However, insulin does not directly cause body fat to increase unless a person is in a caloric surplus, eating more calories than they burn. Insulin doesn’t seem to reduce physical activity levels or cause people to consume more food necessary for substantial weight gain.
Some people believe that eating carbohydrates triggers insulin release, leading to fat gain, and they attempt to counter this by adopting low-carbohydrate diets. However, this often replaces carbohydrates with fats, leading to weight gain since dietary fat can enter fat cells without conversion. Throughout the day, your body alternates between absorbing nutrients and storing fat (postprandial state) and using fat energy stores (postabsorptive state). This cycle balances between “fed” and “fasted” states, storing and burning fat as needed.
Studies that show insulin does not reliably increase hunger in most cases challenge the idea that insulin causes hunger or that high insulin levels are linked to obesity. Furthermore, studies comparing high-carb, low-fat diets to low-carb, high-fat diets have shown no significant differences in weight gain when calories are controlled. Read more https://dhamifitness.com/blogs/f/low-fat-vs-low-carbs-which-one-is-better-for-weight-loss
The glycemic index, which measures how much a food raises blood sugar levels, is often cited as a factor in weight gain. However, foods with low glycemic index values, such as pizza, ice cream, and cookies, can be just as lipogenic as high glycemic index foods. This is because they are calorie-dense and palatable, leading to overconsumption.
Moreover, Insulin signals to the brain indicate a fed state, helping regulate appetite and prevent overeating so it doesn’t even make sense to say more insulin means more fat storage.
Insulin serves various functions in the body beyond blood glucose regulation and fat storage:
In conclusion, we can say that insulin has little to no effects on weight gain unless someone is in a calorie surplus diet. We need to stop blaming insulin for weight gain and focus on eating balanced diet.
Recent reviews criticize CIM, arguing that it is based on misunderstandings and misinterpretations of physiological and metabolic data, particularly in humans, where evidence for the model remains inconclusive.
Despite the uncertainty, there is still support for the idea that diet composition, beyond calorie content, affects metabolism and body weight through hormones, metabolic pathways, gene expression, and the gut microbiome. However, critics argue that the CIM oversimplifies the complex interactions of diet and metabolism, dismissing other potential factors, such as environmental changes in body weight control. High-quality research is needed to resolve these questions and address the rising prevalence of obesity and related health issues.
Ludwig DS, Ebbeling CB. The Carbohydrate-Insulin Model of Obesity: Beyond “Calories In, Calories Out”. JAMA Intern Med. 2018 Aug 1;178(8):1098-1103. doi: 10.1001/jamainternmed.2018.2933. PMID: 29971406; PMCID: PMC6082688.
Schwartz MW, Seeley RJ, Zeltser LM, Drewnowski A, Ravussin E, Redman LM, Leibel RL. Obesity Pathogenesis: An Endocrine Society Scientific Statement. Endocr Rev. 2017 Aug 1;38(4):267-296. doi: 10.1210/er.2017-00111. PMID: 28898979; PMCID: PMC5546881.
^Hua QInsulin: a small protein with a long journeyProtein Cell. (2010 Jun)
^Bentley G, Dodson E, Dodson G, Hodgkin D, Mercola DStructure of insulin in 4-zinc insulinNature.(1976 May 13)
^Thermodynamics of the Hydrophobicity in Crystallization of Insulin
^Bocian W, Sitkowski J, Bednarek E, Tarnowska A, Kawecki R, Kozerski LStructure of human insulin monomer in water/acetonitrile solution Biomol NMR.(2008 Jan)
^Ganim Z, Jones KC, Tokmakoff AInsulin dimer dissociation and unfolding revealed by amide I two-dimensional infrared spectroscopy Phys Chem Chem Phys. (2010 Apr 14)
^Dodson G, Steiner DThe role of assembly in insulin’s biosynthesisCurr Opin Struct Biol. (1998 Apr)
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