David just found out that he had diabetes. His primary care doctor prescribed metformin to reduce his A1c. His goal with diabetes is to lose weight. He is curious whether metformin helps reduce his weight. So he asks does metformin cause a weight loss to his doctor. Let us answer David’s question.
Endocrinologists and diabetologists use metformin as a weight-reducing agent in clinical practice. Of course, weight-loss efficacy is in addition to the glucose-lowering efficacy of metformin.
So, yes, weight loss with metformin is very possible. Although it is variable. For example in one study day found an average weight loss of up to 12 pounds (5.6%) under treatment with metformin for 6 months in overweight, insulin-resistant patients. In patients with diabetes, this is typically 1 to 2%. Approximately half of the studies in drug-naive type 2 diabetic patients demonstrated significant weight loss with metformin. Most of the time the behavioral and dietary intervention will also dictate the amount of weight loss associated with metformin.
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Review of literature about metformin and weight loss
Long-term follow-up from the Diabetes Prevention Program demonstrated that metformin produced durable weight loss. Diabetes prevention program was one of the largest trials ever done for diabetes prevention. Researchers believe metformin does that by decreased food intake. The effect of metformin on appetite is likely to be multifactorial. These effects may include changes in hypothalamic physiology, leptin, and insulin sensitivity.
Does metformin always cause weight loss?
Not every study is conclusive. There are also some conflicting data in the literature in terms of whether metformin causes weight loss. One review analyzing studies describing weight changes under metformin concluded that there is not sufficient evidence to recommend metformin as a treatment of overweight individuals. This may be partially due to the metformin dose. Accordingly, some studies indicate that the weight loss efficacy of metformin can be dose-dependent. For those patients who are not using 2000 or 2500 mg of metformin may not be able to lose weight.
The controversial results may be largely due to different degrees of insulin resistance in the study populations. A Turkish study described an average weight loss of 20 pounds in patients with pronounced insulin resistance.
Another study reported that 25 of 26 severely obese women (refractory to diet) a weight loss of at least 5% within the first 6 months of metformin therapy.
The bottom line, data suggest that the efficacy of metformin to reduce weight depends at least partially depends on the degree of insulin resistance.
Today, we know the strong link between weight gain and insulin resistance There is compelling evidence that insulin resistance is a major contributor to abdominal obesity. Yet, it hasn’t been clarified if insulin resistance leads to or is rather a consequence of obesity.
Improving insulin resistance helps weight loss by the following mechanisms
Metformin not only improves blood glucose control by increasing glucose uptake in tissues but also decreases glucose output from the liver. Metformin causes weight loss by also inhibiting glucose production by the liver. Metformin also reduces glucose absorption from the intestinal system. These mechanisms provide less glucose for energy storage in the fat tissue. Notably, it has been shown that, in contrast to weight loss induced by low-calorie diets, metformin diminishes fat tissue but not lean body mass.
Furthermore, abdominal fat tissue tends to retain its sensitivity to insulin. There typically leads to the persistence of abdominal fat tissue in insulin-resistant obese patients. Restoring insulin sensitivity by metformin reduces insulin secretion. As a result, the insulin receptors of abdominal fat tissue are exposed to less insulin. This, in turn, results in a lower energy uptake by abdominal fat and thereby reduces abdominal fat mass.
Interestingly, however, metformin did also cause significant weight loss in obese patients without insulin resistance. This makes us think of other mechanisms than just reducing insulin resistance. For example, when we use metformin in patients with PCOS who are not obese it still helps them lose weight.
Appetite reduction with metformin
Metformin leads to a decrease in appetite. Some also believe that appetite reduction with metformin may be due to a decrease in leptin levels. Actually studies proved that by showing a reduction in leptin levels in patients taking metformin. Furthermore, GLP-1 levels seem to rise significantly under metformin and may thus promote weight loss. If you remember from our previous blogs we will discuss the weight loss effects of Ozempic and Rybelsus. These drugs are GLP-1 drugs. As a result, they actually cause much more weight loss than metformin. They also create much more appetite reduction than metformin.
We know that patients with severe obesity have a greater capacity to lose weight than patients with relatively mild obesity. For example, a 400-pound patient who loses 5% of their weight with lose 20 pounds whereas a 200-pound patient will lose only 5 pounds. Studies also note that the effectiveness of metformin as a weight-reducing agent was independent of age or sex.
In summary, the literature data suggest that if doctors treat obese patients with metformin in high enough doses it is a beneficial and cost-effective drug to reduce weight. The effectiveness of metformin as a weight-reducing agent is not restricted to insulin-resistant patients. Nevertheless, we still expect a greater weight loss in patients with insulin resistance/metabolic syndrome.
What other benefits metformin can provide?
In addition to weight loss, there are studies suggesting the anticancer effect of metformin. Some suggest metformin can actually reduce heart attacks and strokes as well. Moreover, there is compelling evidence of the antiaging features of metformin. Metformin has effects on cholesterol as well. We will discuss these in the following articles/blog posts.
If you want to learn more about insulin resistance, metabolic syndrome metformin and weight loss associated with metformin please contact us at www.sugarmds.com.
At our diabetes center, we care for diabetes remotely. We can consult, monitor and treat you via telemedicine. We use technology in order to treat all that. Diabetes specialist, diabetes coach, pharmacists worked together to achieve a cost-effective and successful diabetes treatment.