Hormones and Weight Gain - The Role of Insulin

Why Excess Insulin - Not Excess Calories - Makes Us Fat

Mar 2, 2010

Adam Kosloff 

Hormones and weight gain - why insulin is key - Adam K

Why the relationship between hormones and weight gain - specifically the hormone insulin - undermines the conventional theory about what causes obesity.

The hormone and weight gain connection has been known to obesity researchers for over four decades. Many hormones, particularly the hormone insulin, can influence our metabolism. Nevertheless, when most of us think about obesity, we inevitably blame the problem on too many calories in the diet. Why? This article will explain.

The First Law of Thermodynamics and Energy Balance

According to the laws of physics, energy that goes into any system must equal the energy coming out of it. This common sense idea, known as the First Law of Thermodynamics, is true for any system, including the human body. If you were to write this idea as an equation, you would get the following:

• •Energy Stored in the Body = Energy Entering the Body - Energy Leaving the Body
• •This Energy Balance Equation, as it is often called, usually gets shorthanded to become: Energy Stored = Calories In - Calories Out

A "calorie" is simply a unit of heat energy. Specifically, it is the amount of heat it takes to raise a gram of water by one degree Celsius.

From the energy balance equation, researchers derive much of the conventional wisdom about obesity. Raise "calories in" by overeating and lower "calories out" by being inactive, we are told, and the right side of the energy balance equation will get bigger. Hence, we will store more energy in our bodies, presumably as fat. Conversely, lower "calories in" by dieting and raise "calories out" by exercising, and we will presumably get rid of fat.

How Do Hormones and Weight Gain Fit in?

As award winning science writer Gary Taubes has pointed out, most obesity researchers make two critical mistakes when thinking about the energy balance equation:

1. 1.They assume that "calories in" and "calories out" are independent variables. In other words, you can manipulate one without affecting the other. But this assumption clearly does not work. For instance, when you increase "calories out" by exercising a lot, this makes your body crave additional calories to replenish energy lost. You "work up an appetite."
2. 2.They do not allow for the possibility that the fat tissue itself may play a role in energy balance. In other words, we all assume that changes in caloric balance cause changes in energy balance, but it could be the other way around. Changes in energy balance could cause changes in caloric balance. What this means is that some primary hormonal factor could be to blame; overeating and inactivity would then be consequences of obesity as opposed to causes of it.

Getting Rid of Belly Fat - To Do So, You Must Fix the Primary Defect

If excess calories do not make us fat, what does? According to Taubes, we must look at the relationship between hormones and weight gain. It turns out that when our bodies produce too much insulin, this locks excess fat in our fat tissue. Unless you fix this primary problem - over-secretion of insulin - weight loss will ultimately fail, even if you cut calories and exercise more.

Simplifying the science a bit, the chain of cause and effect that connects hormones and weight gain appears to be along the lines of the following:

1. 1.Overeat sugar and carbohydrates.
2. 2.This drives the pancreas to secrete a lot of insulin.
3. 3.Insulin pulls blood sugar into the cells of the fat tissue.
4. 4.The sugar is burned for fuel.
5. 5.A byproduct of this reaction is a molecule called alpha glyercol phosphate.
6. 6.Alpha glycerol phosphate drives the fat cells to store more triglycerides than they normally would.
7. 7.Repeat over time.
8. 8.The result is obesity.

Summary of Relationship Between Energy Balance, Hormones and Weight Gain

Almost all of use were brought up on the idea that calories count more than hormones when it comes to weight regulation. Here is a summary of the key points behind the alternative hypothesis about what causes obesity and how it can be fixed.

• •Energy Stored = Calories In - Calories Out; we get this idea from the 1st Law of Thermodynamics.
• •The Caloric Balance Hypothesis blames obesity on excess calories and reads the equation from right to left: (Energy Stored <= Calories In - Calories Out).
• •The other hypothesis (known as Lipophilia) blames obesity on too much insulin and reads the equation from left to right: (Energy Stored => Calories In - Calories Out).
• •The hormone insulin plays a crucial role in energy balance in the body.
• •Eating too many carbohydrates (and other factors) can make you produce too much insulin.

Sources:

Telegraph.co.uk, *"Big Fat Lie" (accessed March 4, 2010).

NPR.org, *"Not All Calories Are Created Equal, Author Says" (accessed March 4, 2010).

*Taken from: http://www.suite101.com/content/hormones-and-weight-gain---the-role-of-insulin-a209607