Achieving weight loss was once viewed as being as simple as “use more energy than you take in.” But despite the vast number of weight loss programs in existence today, many overweight individuals are not successful at their valiant attempts to exercise more and eat less. Even if they do lose weight initially, many do not keep it off long-term. Obesity is now an epidemic in the U.S. and in many other parts of the world. The associated health complications are serious and the burden on our healthcare system is immense. It has become clear that there is more to the story than just “calories in, calories out.”
More research has been conducted in recent decades, hoping to solve the mystery of why so many obese individuals appear to be resistant to weight loss even with their best efforts at diet and exercise. One important clue has emerged that could play a major role in developing new approaches to fight obesity and help those struggling to achieve a healthy body weight.
A study published in 2015, found that individuals with a body mass index (BMI) greater than 30 had daytime core body temperatures that were significantly lower than the leaner participants. Although the sample size was small, the other factors that would normally affect body temperature (and confound the study) were well controlled. This difference in body temperature reflects a lower metabolic rate in the obese individuals and could account for a weight gain of about 4-5 lbs per year. This is consistent with the gradual weight gain over time (as well as difficulty losing weight) that many overweight individuals report.
This link has been explored in the past as it relates to a thyroid condition known as Wilson’s syndrome. In this condition, patients often have normal TSH (thyroid stimulating hormone) and T4 (thyroxine), but experience symptoms typically associated with hypothyroidism such as depression, fatigue, aches and pains, cognitive dysfunction, and weight gain. This is due to poor conversion of T4 (inactive thyroid hormone) to T3 (the active form). The conversion occurs mostly within brown fat – the type of body fat that generates heat, which explains why blood levels of thyroid hormones could still be normal. Interestingly, T3 is directly involved with maintaining body temperature and starting targeted treatment with sustained-release T3 has been shown to correct basal body temperature and help those with Wilson’s syndrome feel remarkably better.
Although the reason for the low body temperatures in the study referenced above was not explored, it is likely that some (if not all) of the participants had this same problem with converting T4 to T3. Physicians who are treating Wilson’s syndrome with T3 have seen improvements not just in their patients’ symptoms, but also impressive weight loss once their body temperatures normalized. This occurred without any changes in the patient’s diets or exercise routines. In one 2006 study, all of the patient’s body temperatures normalized, with treatment length varying from 3 weeks to 12 months.
In some cases weight gain happens because of ingesting too many calories and not getting enough exercise. But often, it is a bit more complicated. It may be that this “biological handicap” of a low core body temperature is playing a role in your difficulty losing weight. It is a good idea for anyone who is overweight to monitor their temperature to detect if it is consistently lower than 98.5 degrees (Fahrenheit) and especially if it is often lower than 97.8 degrees (Fahrenheit). This is a good indicator of a slow metabolism that could be stalling weight loss efforts and leading to further weight gain. Whether the root cause is a poor conversion of inactive to active thyroid hormone or another yet-to-be-determined factor, it is clear that this is an important finding that will shape future research and treatments for obesity.
If you’re frustrated and can’t lose weight (or can’t keep it off), be encouraged and find a health care provider that is knowledgeable on this topic!
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