Understanding what hormones regulate your metabolism is the first step in learning how to set your body up for optimal fat loss. Everyone has a unique resting metabolic rate determined by the amount of lean muscle they have, genetics (DNA makeup), and hormonal balances. The secret to successfully increasing your metabolism and burning fat revolves around creating the optimal hormonal balances for maximizing your metabolic rate.

You probably already know that calorie restriction dieting can cause your metabolism to slow down and bring weight loss to a halt. The good news is metabolic slowdown doesn’t have to happen. Once you understand why it happens, you can take a number of steps to avoid it.

Regulating thyroid hormone levels is the cornerstone to keeping your metabolism running on high. The thyroid gland is the main regulator of your overall metabolism. It sets your body temperature after the hypothalamus says make it so.

How your thyroid gland works…

The thyroid gland secretes two types of thyroid hormones, T4 and T3. Although most of the thyroid hormone in blood circulation is T4, it’s T3 that really produces the most impact. At the cellular level, T3 is the one that hooks up to the receptors and makes everything work. The main cause of metabolic slowdown is a decrease in active thyroid hormone.

There are three main reasons why thyroid hormone levels will go down:

1. The loss of lean muscle

The loss of lean muscle comes from a lack of resistance training, protein deficiency, and low calorie diets that force the body to break down muscle tissue. There are also hormonal changes in estrogen and testosterone that naturally decline as you age that can create muscle loss. The good news is you have a significant degree of control over all these factors.

2. Increased production of cortisol

The second cause of thyroid hormone attenuation is the increase in cortisol levels. Cortisol is a hormone produced by the adrenal glands in response to psychological and physiological stress. When the cortisol receptors on the pituitary gland are activated, they reduce production of thyroid stimulating hormone (TSH), which is the messenger between the hypothalamus and the thyroid gland.

Cortisol also affects the conversion process of T4 (circulating thyroid hormone), to T3 (the thyroid hormone that hooks up to the receptors). Stress, overtraining, low calorie diets, and a lack of sleep all contribute to the increase in cortisol and a decrease in thyroid hormone production.

3. Increased production of insulin

The third cause of decreased thyroid hormone production is the constant presence of insulin. The pancreas secretes insulin in response to high blood sugar levels. If the body experiences high blood sugar levels on a regular basis (too much carbohydrate in the diet) the cells start to reduce their acceptance of insulin. This is commonly referred to as insulin resistance. The resulting over-secretion of insulin causes cortisol levels to rise which as you just learned can reduce thyroid hormone production.

Bottom line is the lack of lean muscle, from all the causes, too much stress, and a poor diet can all contribute to a decreased thyroid hormone production and slowed metabolism.

The role of growth hormone, adrenaline and nor-adrenaline

Your metabolism is also regulated by the balances of powerful fat burning hormones which can be increased with the right type of exercise. The right type of exercise? Yes, while all exercise is beneficial, high intensity- short duration “burst trainingexercise produces the best results.

The short bursts of all out effort in these routines will cause an increase in growth hormone and the adrenal hormones adrenaline and nor-adrenaline. Traditional long-slow-distance cardio (aerobic training), and low-intensity resistance workouts simply won’t produce the same hormonal response. In fact, excessive aerobic exercise can actually have a negative impact on these anabolic hormones.

As a certified Charleston personal trainer, I’m always educating my clients on the idea that more is not always necessarily better with exercise. It’s what you do for your exercise and not how long you do it.

How to optimize your metabolic rate

Here are some ways you can optimize your metabolic rate and set the right conditions for fat loss and increased lean muscle development:

- Perform burst training (resistance workouts) and interval training (cardio workouts) to raise growth hormone, adrenaline, and nor-adrenaline levels.

- Avoid low calorie diets that can reduce thyroid hormone production.

- Minimize stress to avoid excess cortisol production.

- Reduce insulin levels by eating a supportive nutrition diet with moderate levels of carbohydrates.

- Increase protein intake to help with lean muscle development and prevent muscle catabolism

- Get plenty of sleep (7-8 hours) to help with growth hormone secretion and reduce the production of cortisol.

While this is a solid set of guidelines to help you increase your metabolic rate, there are instances where decreased thyroid hormone production is the result of an auto-immune disease or other imbalance with the thyroid gland.

If you suspect decreased thyroid hormone production there are three specific tests you should request from your physician.

Thyroid Stimulating Hormone (TSH) Test
Free T4 Test
Free T3 Test

Just looking at one test alone is a poor strategy. All three tests are needed to see what’s really going on. You’ll also want to find physician who will work with you to optimize your thyroid levels, not just look to see if you’re in the “normal ranges.”

The bottom line is fat loss is 100% controlled by the hormonal balances in your body. You simply cannot starve yourself on calorie restrictive diets or do excessive exercise and expect your body not to adjust hormonal levels accordingly. If you want to lose body fat, support your metabolism by providing adequate fuel for energy demands from natural, whole foods. Combine a supportive diet with burst training for exercise and you’ll have the best one-two punch available to reduce your waistline.

Author's Bio: 

Shane Doll CPT, CSCS is a certified Charleston personal trainer, fat loss expert, speaker and founder of Shaping Concepts Personal Training Studios. As a specialist in burst training for body transformation and weight loss he provides nutrition and fitness coaching along with e-books, videos, and other resources on his website: www.shapingconcepts.com. To learn more about burst training download his FREE e-book “The Essentials Of Burst Training Workout Program Design.”