Intermittent fasting doesn’t slow down metabolism

Thyroid Metabolism Intermittent Fasting Banner

On START Wellness, the thyroid is not affected during intermittent fasting, but just its function. During intermittent fasting, metabolism doesn’t slow down.

The benefits of your START Wellness intermittent fasting and water program, found in human research so far, include weight loss, improvements in blood sugar, reduced insulin resistance, reduce levels of inflammation within the body. Some people think that intermittent fasting may affect the thyroid functions and thus a slow down in metabolism. But, the research done over the years proves otherwise.

Certain foods like iodized table salt, seafood, bread, milk contain iodine. When we consume them, the iodine passes into the blood. The thyroid is a gland that takes in iodine and combines it with tyrosine to actually create thyroid hormones T3 and T4.

  • The pituitary gland, in the brain, releases TSH (thyroid-stimulating hormone).
  • TSH then stimulates the release of T4 (inactive) hormones from the thyroid gland.
  • T4 is then converted to T3 (active) hormones from the thyroid gland. T3 is increasing the heart rate, increasing your core body temperature, and revving up your metabolism.

As the thyroid gland produces thyroid hormones, it stores them in a large number of microscopic, spherical-looking follicles. When the body needs thyroid hormones, the thyroid gland secretes them into the bloodstream in amounts appropriate to meet the metabolic needs of the cells.

Thyroid Intermittent Fasting

The thyroid gland is controlled by the pituitary gland. The pituitary gland sends messages to the thyroid gland, telling it how many hormones to produce. Normally, the thyroid gland releases the right amount of thyroid hormones for the body to function optimally. External factors disrupt this connection in two ways:

  1. In the case of hypothyroidism, low levels of thyroid hormones can cause fatigue, depression, weight gain, constipation, dry skin, increase cholesterol levels and it can slow down heart function.
  2. In the case of hyperthyroidism, the cause is an existing thyroid condition. A person with a hyperactive thyroid produces too many hormones and has a fast metabolism. A high level of thyroid hormones causes insomnia, fatigue, mood swings, excessive sweating, unexplained weight loss, continuous thirst.

In a 1978 and a 1980 study, obese human subjects were put on a fast for several days. Everyone’s TSH and T4 went up during the fast and T3 dropped. When they supplemented T4 during the fast, T3 still dropped. When they supplemented T3, T3 was maintained.

There are 2 more recent studies: a 2008 study and a 2014 study in the European Journal of Endocrinology and both conclude the same thing. After 10 days of fasting, there was a slight decrease in T3 during the fasting period but there was no change in T4 or TSH.

This means that multi-day fasting is affecting the active form of thyroid while they were fasting, but it didn’t actually mess up the process of creating thyroid long term. So, you are not permanently slowing down your metabolism.

On your START Wellness intermittent fasting and water program, what you are doing is temporarily reducing your thyroid, which is active in the body, but only during the period in which you are fasting. Once you break your fast, you’re metabolism revs back up so much that it actually compensates for the slow thyroid production during your fast. So, you end up ahead of where you were before.

Most of these studies are carried out over 4-10 days too. As soon as the subjects in these studies ate, their levels returned to normal.

Taking an example of religious fasting practiced by hundreds of millions of people across the globe, in Ramadan fasting, for example, you eat before sunrise and fast until sunset. During the fast, you abstain from both food and drink. There was a study published in the Journal of Medical Science that was done on 42 Jordan subjects that were going through Ramadan. They tested blood markers and what they ultimately found was that:

  • There were some changes in LDL cholesterol, HDL cholesterol, fasting blood glucose,
  • There was barely any change in T3, but no change in T4, TSH.

However, what causes massive weight gain for some during the religious fasting periods is how they simply break their fast. Breaking your fast the right way by not combining fats and carbs is critical. Sadly most during their religious fasts, break their fast with many sweets, or combine hefty carbs and fats only to eventually gain a lot of weight and place undue pressure on their system, simply undoing all the benefits of the fast, in effect.

People say that intermittent fasting affects the hypothalamic-pituitary-thyroid axis. This is correct, but it does not affect you in the way that your body cannot produce it anymore. It only temporarily affects the production. It’s no different than the temporary reduction of testosterone production only to have it come back soon as your done fasting. All these things don’t really matter, as long as your body overall is in homeostasis.

People also tend to think that whenever we don’t eat, our metabolism slows down, and eventually if our caloric intake is too low our metabolism can start to slow down. But that is only if you are reducing your calorie intake for a long period of time as the body adapts to the same. That is also why the calorie in calorie out theory is dated.

If you only consume 1,000 calories every day, eventually, your metabolism is going to adjust to that. It’s not about what you’re not eating it’s about how much you actually are eating. So, if you are fasting, it’s important to make sure you’re caloric intake is still high enough that you are not lowering your basal metabolic rate. That’s why on START Wellness it’s paramount you consume all your daily caloric intake within your 8 hour eating window.  

The thyroid gland is a sensitive barometer of overall caloric sufficiency in the body. T3 has the job of stimulating metabolism in every cell in our bodies, including our muscle cells. In the presence of caloric restriction, thyroid hormone will breakdown muscle and fat.

During your START Wellness intermittent fasting and water program, you burn your fat stores and ketones. So we don’t need that much T3 to stimulate skeletal muscle cell catabolism. Our body responds by inactivating the T3 hormone and T4 is converted to inactive reverse T3. It is a mechanism within our bodies to prevent our muscles from breaking down during periods of low food intake.

Your START Wellness intermittent fasting and water program should fit into a regular routine to give your body a break from eating too much and to stimulate autophagy. START Wellness blends in seamlessly in a way to support your exercise routine and daily work life. The thyroid requires nutrients like iron, iodine, zinc, selenium, and B-vitamins to produce enough T4 and convert T4 into your active T3 hormone. Your body needs vitamin A and zinc to effectively move the active thyroid hormone into the cells.

So, you shouldn’t be worry that your START Wellness intermittent fasting program is slowing down your metabolism. More important is to be careful to have a correct caloric intake per day, eat plenty of fresh, healthy food. The thyroid will adapt to your lifestyle.

In just 7 days you’ll FEEL the change.
In 30 days you’ll BE the change.
All you have to do is START!

Learn more about START Wellness – Best Intermittent Fasting & Weight Loss App 2021