Hypothyroidism and Intermittent Fasting: What You Need to Know

Intermittent fasting offers numerous health benefits, ranking alongside popular dietary strategies like calorie restriction and the keto diet. Its appeal lies in its potential to improve metabolism, support weight management, and promote cellular health.

Hypothyroidism, a common thyroid disorder, has doubled in prevalence in the U.S. over the past two decades, prompting many to seek alternative solutions. Can people with hypothyroidism practice intermittent fasting? Yes, but it may exacerbate symptoms. Intermittent fasting should be done under medical guidance, tailored to the individual’s health history, and with careful adherence to safety guidelines.

Let’s delve into the workings of intermittent fasting and its potential to improve hypothyroidism symptoms.

What Is Hypothyroidism?

Hypothyroidism is an endocrine disorder in which the thyroid gland doesn’t produce sufficient thyroid hormones. Common symptoms of hypothyroidism are fatigue, slow metabolism, brain fog, weight gain, and cold sensitivity.

What Is Intermittent Fasting?

Intermittent fasting is a dietary approach where individuals eat only during specific windows of time throughout the day. Its variations adapt to different routines and commitment levels, varying in intensity and fasting period duration. The most commonly practiced methods are 16:8 for weight loss, 14:10, and 20:4. Variations in intermittent fasting regimens adapt to any routine, where you can set your eating window early in the morning, during working hours, or at the end of the day, whichever works best for your lifestyle. Take the Fastic quiz for a personalized fasting schedule according to your preferences, eating habits, and everyday responsibilities.

Contrary to other dietary methods, intermittent fasting focuses on when you eat and not what you eat. During eating windows you can eat whatever foods you want, whereas, during fasting periods you can only drink calorie-free beverages, such as water, fruit-infused drinks, and plain-black coffee.

Health Benefits of intermittent fasting

The potential benefits of intermittent fasting include:

Important to note: Each person’s body is unique and may react differently to intermittent fasting, with varying results based on individual metabolism, lifestyle, and health conditions.

How Does Hypothyroidism Affect Metabolism and Energy?

Let’s explore the key hormones involved in regulating metabolism and energy production.

Triiodothyronine (T3): T3 is the active thyroid hormone that directly regulates metabolism, energy production, and heart rate.

Thyroxine (T4): T4 supports metabolism, and overall energy levels indirectly, as T4 is converted to T3 in tissues.

Thyroid-stimulating hormone (TSH): TSH signals the thyroid to produce T3 and T4, helping maintain stable levels of these hormones in the bloodstream, which is crucial for balanced metabolic function.

T3 and T4 control how cells convert nutrients into energy, affecting overall energy levels and calorie burning. Low thyroid hormone levels can slow metabolism, making weight loss more difficult, often leading to fatigue, and making weight management more difficult.

Potential Benefits of Intermittent Fasting for People with Hypothyroidism

Intermittent fasting can provide many benefits when practiced safely and under the guidance of a qualified healthcare professional.

Here are some ways intermittent fasting can help with hypothyroidism symptoms:

1. Support Weight Management

After 12 to 36 hours of fasting—depending on baseline glycogen stores, physical activity, and metabolic rate—the body enters a state of ketosis, where it starts to burn stored fat for energy due to the lack of caloric intake. Intermittent fasting promotes weight loss effects similar to traditional calorie-restriction diets. A systematic review of 27 trials investigating intermittent fasting as a treatment for obesity revealed promising results. A New England Journal of Medicine study found that people limiting calories alone lost similar weight to those eating within a limited time window.

2. Reduce Inflammation and Enhance Cellular Repair

A recent study showed how fasting can attenuate proinflammatory cytokines and immune cells. Read more on how fasting may benefit Hashimoto’s disease. Moreover, studies show that fasting promotes autophagy, a process by which cells renew themselves. Cellular renewal can enhance mitochondrial health, promoting improved energy production.

3. Improve Mental Clarity and Focus

Fasting can improve brain fog symptoms through autophagy, which has been demonstrated to support neurogenesis and neuronal development production. Ketones, produced during fasting, trigger biological reactions that activate the brain-derived neurotrophic factor (BDNF) gene. BDNF serves as a neurotransmitter modulator and participates in neuronal plasticity, essential for learning and memory.

4. Potentially Aid with Cold Sensitivity

A study on intermittent fasting as an approach to treat obesity-related diseases in mice found that an every-other-day fasting regimen can promote the beiging of white adipose tissue (WAT), stimulating the development of beige fat. Beige fat functions similarly to brown adipose tissue (BAT), generating heat through non-shivering thermogenesis. This process enhances the body’s ability to regulate temperature in cold conditions. However, further research is needed to determine whether these findings apply to humans.

Possible Risks and Considerations of Intermittent Fasting with Hypothyroidism

The following are potential risks associated with intermittent fasting in individuals with hypothyroidism:

Worsening of fatigue and sluggishness

Reduced food intake from fasting may slow metabolism, further decrease energy levels, and potentially impair thyroid hormone production, exacerbating existing fatigue symptoms.

Lead to nutritional deficiencies

Due to its shortened eating windows, fasting can lead to an inadequate intake of essential vitamins, minerals, and macronutrients. Learn more about taking vitamins while fasting.

Higher risk of hormonal imbalance

Fasting can lead to hormonal imbalances by interfering with various physiological processes, which may further worsen thyroid hormone imbalances.

Affect thyroid hormone conversion

Fasting can increase cortisol levels due to the stress it places on the body. Elevated cortisol levels can inhibit the conversion of T4 to T3, reducing the levels of active thyroid hormones.

Tips for Intermittent Fasting with Hypothyroidism

If you are considering intermittent fasting, follow these recommendations to ensure a safe and enjoyable experience.

Gradual approach: Ease into the fasting routine by starting with shorter fasting periods and gradually increasing the duration. This approach allows your body to adjust to the new eating schedule without overwhelming it.

Nutrient-dense diet: Focus on integrating a nutrient-rich diet during eating windows. Prioritize whole foods high in vitamins, minerals, and fiber to support metabolism and energy levels.

Optimal hydration and electrolyte balance: Maintain proper hydration and electrolyte levels, especially during fasting periods. Drink plenty of water and replenish electrolytes by taking calorie-free supplements and electrolyte-rich drinks.

All in all, intermittent fasting is a feasible option to ameliorate hypothyroidism symptoms. Nonetheless, your doctor will know better if it’s the best strategy to treat your particular hypothyroidism symptoms. Explore how the Fastic app can support your intermittent fasting journey, especially with managing hypothyroidism, and help you achieve balanced and sustainable results.

Disclaimer: It is advised to speak with a health professional before beginning intermittent fasting or a diet program. There may be side effects for people with certain medical conditions.