Insulin Weight Gain Is a Common Side Effect of Insulin Therapy: Why?

Insulin weight gain frustrates millions of type 2 diabetics who depend on shots of the hormone to stave off hazardous symptoms of their diabetes. Why does this side effect occur? If insulin therapy does cause the accumulation of adipose tissue, what could that tell us about the fundamental nature of obesity and overweight?

This site has examined two theories about what causes obesity:

The Caloric Balance Hypothesis says we should only be able to accumulate fat on insulin therapy if the therapy somehow changes our balance of "Calories In" and "Calories Out" -- by, for instance, making us hungrier or making us less prone to exercise.

The Lipophilia Hypothesis tells us that insulin weight gain happens because insulin drives the accumulation of triglycerides in the fat tissue. Insulin regulates the deposition and mobilization of fat in the fat tissue, as science writer Gary Taubes (and others) have pointed out.

So can we find evidence to support either of these two hypotheses? In fact, nearly everywhere we look, we see confirmation of Lipophilia.

1. Consider this article from Diabetes: A Journal of the American Diabetes Association: "Intensive insulin therapy and weight gain in IDDM."[1]

In the abstract, the authors state: "Intensive insulin therapy is frequently complicated by excessive weight gain."

In their study, they found that: "Body weight increased 2.6 plus or minus 0.8 kilograms with intensive insulin therapy... as a result of an increase in fat mass."

2. As Christian B. Allen and Wolfgang Lutz explain on page 3 of Life Without Bread:[1]

"Insulin is released into the bloodstream to perform two main functions:

1. Insulin's primary role is to transport glucose into the cells to be used for energy. Glucose is a simple sugar formed from the breakdown of all carbohydrates in the intestines in the stomach.

2. The second function of insulin is to help convert and store that sugar as glycogen in the liver and as fat in fat cells. The fat is stored in the form of triglycerides (also called triacylglycerides) in adipose tissue."

3. Many researchers passionately support the contention that insulin serves as the gatekeeper for how much fat we accumulate in the fat tissue. This concept is the premise of practically every mainstream low carb diet plan out there, including:

4. Nodules of fat form at insulin injection sites. Seriously, what more evidence do you need? Even if you somehow could discount all insulin weight gain as somehow resulting from an imbalance of calories, how can you possibly "explain away" these nodules of fat as resulting from a positive caloric balance? The body doesn't just arbitrarily decide to accumulate fat in the precise location of the injection site as coincidence, does it? But if insulin can be "blamed" for creating these fat nodules, how can you deny that insulin plays a key role in fat deposition in general? And once you admit that insulin plays a key role in fat deposition, how then can you continue to support a paradigm that tells us that calories control how much fat we accumulate?

Every single instance of insulin weight gain -- unaccompanied by changes in diet and exercise -- is another piece of evidence against the Caloric Balance Hypothesis.

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1. M G Carlson and P J Campbell. "Intensive insulin therapy and weight gain in IDDM." Diabetes December 1993 vol. 42 no. 12 1700-1707.

2. Allan, Christian and Lutz, Wolfgang. "Life Without Bread." p 3. New York: McGraw-Hill (2000).

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