I see many patients who want to “speed up their metabolism”, but the first question you need to ask is how do you even check how fast your metabolism is to begin with and how do you know it’s improving?
Well there is a simple, free and awfully underutilized way to assess your metabolic rate and that is…your body temperature!
Proper body temperature is not regulated just for the purpose of keeping you warm. Body temperature affects every process in your body, one of which is the ability to burn calories. In fact, there is growing scientific interest in using core body temp as a target for treatment of obesity.
Do you know what else is directly responsible for maintaining body temperature? T3! T3 is the active form of our thyroid hormone that gets converted from T4, our inactive thyroid hormone. Therefore, checking your body temperature is also a direct indication of thyroid function.
If your body temperature is consistently low (less than 36.5 C), there’s a good chance that you have slow metabolism. It may also mean that you are not converting enough T4 (inactive) to T3 (active thyroid hormone).
There is a great study published in the Chronobiology International Journal in 2015 that compared the core body temperature of obese and lean females. What they found was that obese women had lower core body temperature (by approximately 0.35⁰C), specifically during the day, whereas there was no difference during the night-time hours.
Low body temperature indicates a reduced ability to “spend energy” and hence a lower metabolic rate. This can result in long-term weight gain of about 4-5 lbs per year. Normalizing your body temperature can be pivotal in improving your weight loss efforts and improving your energy levels.
So how do you go about checking your temperature?
Using a home thermometer, it’s best to check several times during the day-time and get an average. If you are a menstruating woman, I would recommend taking measurements on several days throughout the month to account for the fluctuations related to ovulation. Also wait 30 minutes after drinking cold or hot beverages.
It doesn’t matter which site you use, as long as you are consistent and you use the normal reference ranges appropriate for that site. Normal ranges are 36.5-37.5⁰C, but they tend to be higher if measured in the ear or rectally versus orally, and may be even lower if measured in the armpit.
Tips for normalizing body temperature:
- Thyroid nutrient support – vitamins that support the thyroid can help boost T3 production and hence restore your body temperature. These include iodine, selenium, zinc, vitamin A, and omega-3. Make sure if you are taking any supplements you are properly supervised by a practitioner who is knowledgeable in their use. Taking too much or a supplement that is inappropriate for your specific case may potentially make things worse.
- Warm spices – such as cayenne, ginger, cinnamon and tumeric – help increase thermogenesis
- Coconut oil – is broken down in the body and converted to energy rather than being stored as fat, and this can kick up your core temperature.
- Thyroid replacement – as a last option or if your thyroid levels are actually abnormal, you may need thyroid replacement in the form of T4 (the conventional treatment) or T3 or desiccated thyroid. Speak to your practitioner about which option is most appropriate for you.
In summary, assessing for your baseline metabolic rate is in fact quite simple and accurate. It’s also easy to assess improvements or your response to medications, vitamins and other lifestyle and dietary changes. Give this a try, numbers don’t lie!
References: Grimaldi D, Provini F, Pierangeli G, et al. Evidence of a diurnal thermogenic handicap in obesity. Chronobiol Int. 2015 Mar;32(2):299-302.