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The Sirtfood Diet, Hypothyroidism, and Hashimoto's

Is the popular Sirtfood diet safe and effective for people with autoimmune Hashimoto’s disease and an underactive thyroid?
The Sirtfood Diet, Hypothyroidism, and Hashimoto's
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The Sirtfood diet is a trendy and controversial diet that has gained attention due to a bestselling book, its association with celebrities, and its unique approach to weight loss. The Sirtfood diet focuses on eating sirtuin-activating foods, also known as “sirtfoods,” which are believed to improve metabolism and speed weight loss. The diet features significant calorie restriction and strict fasting rules. In this article, find out more about the Sirtfood diet and whether it is a safe and effective option for people with hypothyroidism.

Growing interest in the Sirtfood diet

The bestselling Sirtfood Diet book, written by nutritionists Aidan Goggins and Glen Matten and published in 2018, introduced the concept of “sirtfoods. “This term refers to a group of foods rich in nutrients that are believed to activate the body’s “skinny genes” and improve overall health. The book outlines a dietary plan incorporating these sirtuin-activating foods. It claims that people can lose weight, enhance their resistance to disease, and boost energy levels when following the diet.

Widespread interest in the Sirtfood diet first exploded after it was widely claimed in the popular press that superstar singer Adele followed the diet to lose more than 100 pounds. (The pop diva has repeatedly denied this, stating in interviews that an intense exercise regimen was responsible for her remarkable weight loss success.) Pippa Middleton – sister of Catherine, Duchess of Cambridge – reportedly followed the Sirtfood diet before her high-profile wedding to James Matthews in 2017. Conor McGregor, Irish mixed martial artist and professional boxer, has also been associated with the Sirtfood diet. Public attention to the diet was further fueled when McGregor posted an image of himself reading the Sirtfood Diet book on Instagram.

What are sirtuins?

Before we get into the specifics of the diet, let’s talk about sirtuins. They are a family of proteins found in the cells of all living organisms, where they regulate various processes in the body, including metabolism, inflammation, and aging. In mammals, there are seven different types of sirtuins, named SIRT1 to SIRT7, each with specific functions.

Sirtuins reportedly act as metabolic sensors, meaning they can respond to changes in the body’s energy levels. Sirtuins change other proteins in the cell, affecting how these proteins function and influencing processes such as how the body uses and stores energy. Sirtuins have been studied for their potential role in promoting health, improving metabolism, reducing inflammation, and increasing longevity.

What are Sirtuin activating compounds (STACs)

There are a number of foods that can activate sirtuins in your body, although the amount needed in humans is still unknown. These foods are high in what are known as sirtuin-activating compounds, or STACs. STACs are considered caloric restriction mimetic compounds, meaning they may mimic the effects of caloric restriction, which has been linked to potential health benefits. The discovery of STACs is considered a significant achievement. Still, further research is needed to fully understand their effects and potential therapeutic applications.  Examples of STACs include resveratrol, quercetin, butein, piceatannol, isoliquiritigenin, fisetin, melatonin, and oligonol.

What types of foods are “sirtfoods?”

“Sirtfoods” include various plant-based options rich in STACS and bioactive compounds that have been shown to activate sirtuins. Because it’s plant-based and doesn’t include animal protein or dairy, the Sirtfood diet can be easily adapted for vegetarian or vegan diets. It’s also naturally gluten-free.

How to follow the Sirtfood diet

The Sirtfood diet is designed around activating sirtuins by eating “sirtfoods.” The diet is divided into two phases, each with specific steps and duration.

Phase 1

During Phase 1, which lasts a week:

  • Days 1-3: Eat no more than 1,000 calories per day, and consume three Sirtfood green juices (made of kale, arugula, flat-leaf parsley, celery, green apple, fresh ginger, lemon, and matcha) daily, plus one meal of sirtfoods.
  • Days 4-7: Eat up to 1,500 calories maximum per day, and consume two sirtfood green juices and two sirtfood meals daily.

Phase 2

During Phase 2, which lasts for two weeks:

  • Consume three meals high in sirtfoods and one sirtfood green juice daily. This phase is designed for steady weight loss.

After completing the initial three weeks, individuals are encouraged to continue incorporating sirtfoods and the diet’s signature green juice into their regular diet.

Foods you shouldn’t eat on the Sirtfood diet

Here are the foods that are generally recommended to avoid or limit on the Sirtfood diet:

  • Baked goods/desserts: These are typically high in sugar and unhealthy fats, which are not in line with the principles of the Sirtfood diet.
  • Fats other than extra-virgin olive oil: The diet emphasizes using extra-virgin olive oil and discourages other types of fats.
  • Processed convenience foods: These often contain high levels of unhealthy fats, sugars, and additives, which are not in line with the diet’s principles.
  • Fatty cuts of meat: The diet encourages lean protein sources and limits the consumption of fatty meats.
  • Grains other than those listed as sirtfoods: While the diet allows certain grains like buckwheat and quinoa, it advises against other types of grains.
  • Fish that are high in mercury: The diet does not specifically list which fish to avoid, but it’s common to limit fish high in mercury, such as shark, swordfish, king mackerel, and tilefish.
  • Processed meats: Processed meats such as bacon, salami, and ham are discouraged as they are processed foods.
  • High-sugar foods: The diet generally discourages the consumption of added sugars, so high-sugar foods like candies, sugary drinks, and sweetened snacks should be avoided.

Why nutritional experts aren’t fans of the Sirtfood diet

One 2022 review article published in the journal Foods reviewed the potential benefits of sirtfoods. The authors concluded that sirtfoods have various health benefits and can help manage metabolic disorders. These foods, whether consumed individually or in combination, can play a role as functional foods that promote better health. The study recommends conducting further research and clinical trials to understand the potential advantages and issues associated with sirtfoods, their effects on the body, interactions with gut bacteria, and the appropriate dosage.

Despite the positive health benefits of sirtfoods, nutritional experts and dietitians have expressed concerns about the Sirtfood diet itself. The diet’s emphasis on specific sirtfoods and its promise of rapid weight loss and greater longevity are met with warranted skepticism and criticism from many in the nutrition world. Here are some key reasons dietitians have raised objections to the Sirtfood diet.

Lack of scientific evidence

One of the primary concerns about the Sirtfood diet is the lack of substantial scientific evidence to support the diet’s claims related to weight loss and health benefits. While the foods recommended by the Sirtfood diet are generally healthy, there are no long-term human studies to determine whether consuming a diet rich in sirtuins has any real health benefits regarding weight loss or other outcomes.

Extreme nature and lack of structure

Dietitians have criticized the Sirtfood diet for its extreme and highly restrictive nature. The diet’s initial phase, which involves consuming only 1,000 calories per day, is considered by many to be unsustainable and potentially detrimental to long-term health. Additionally, the diet lacks comprehensive guidance on maintaining healthy eating habits for the long term, which raises concerns about the potential for adopting disordered eating habits and experiencing nutritional deficiencies.

Focus on caloric restriction

The diet’s emphasis on caloric restriction as a primary mechanism for weight loss is at odds with the recommendations of many credentialed weight loss experts, who typically advocate for a more moderate and sustainable approach to weight management. The promise of losing up to seven pounds in seven days, as claimed by the Sirtfood diet, is considered by many to be controversial and potentially unhealthy.

Lack of clarity on how it works

There is uncertainty about whether the reported benefits of the Sirtfood diet are due to the specific “sirtfoods” recommended by the diet or the overall caloric restriction it entails. This lack of clarity has led to questions about the diet’s underlying mechanisms and the extent to which it can deliver on its purported benefits.

Other concerns about the Sirtfood diet

The Sirtfood diet, like many other restrictive diets, carries certain risks and concerns. Here’s a rundown of some other potential concerns associated with the Sirtfood diet.

Low-calorie intake

The diet involves significant calorie restriction, which can lead to lightheadedness, headaches, nausea, and fatigue. It also can have adverse effects on metabolism in hypothyroidism and Hashimoto’s patients, as discussed in the next section.

Nutritional deficiencies

Due to the focus on a limited number of foods, there is a risk of not obtaining an adequate variety of nutrients, potentially leading to deficiencies.

Disordered eating habits

Repeated exposure to restrictive diets like the Sirtfood diet may lead to the adoption of long-term disordered eating habits.


The extreme nature of the Sirtfood diet and its heavy focus on calorie counting and food restrictions may make it difficult to follow long-term.

Potential side effects

The low-calorie nature of the diet may lead to unpleasant side effects such as impaired mental focus, bad breath, and digestive issues like constipation due to inadequate fiber intake.

Sirtuins, hypothyroidism, and Hashimoto’s

Is the Sirtfood diet safe and effective for thyroid patients? The truth is, we don’t have an answer at this point. There is almost no research on the Sirtfood diet’s effectiveness in the general population regarding weight loss and other health benefits. And there is no specific research on the Sirtfood diet for people with thyroid conditions, including Hashimoto’s thyroiditis and hypothyroidism.

We do know, however, that there may be a potential benefit in activating sirtuins because they’re involved in thyroid activity. Specifically, research has shown that sirtuins help enhance the activation of the T3 hormone in the liver.

We also know that sirtuins can help reduce the risk of developing an autoimmune disease. They can also help with managing flare-ups (22).

It’s essential to be aware that severe calorie restriction, such as the calorie intake recommended in the Sirtfood diet, is not recommended for people with hypothyroidism. Hypothyroidism can lead to a reduced ability to metabolize calories – a slowed metabolism --  and cutting back on calories doesn’t necessarily result in weight loss due to the body’s decreased metabolic rate. Extended low-calorie diets have been shown to negatively affect thyroid function and may even lead to hypothyroidism or worsen the condition.

Research has also demonstrated that caloric restriction decreases the concentration of the thyroid hormone triiodothyronine (T3), the active thyroid hormone at the cellular level. Additionally, a study on obese women showed that a very low-calorie diet led to significant reductions in T3. Clearly, severe calorie restriction can have adverse effects on thyroid function and overall health in individuals with hypothyroidism. It’s crucial for individuals with hypothyroidism to focus on consuming enough calories to support their bodily functions and to ensure they receive essential nutrients for optimal organ function, including thyroid health. This may make weight loss with hypothyroidism incompatible with the Sirtfood diet.

Severe calorie restriction is also not recommended for people with Hashimoto’s disease who are looking to lose weight. In addition to the effects on thyroid hormone levels, chronic calorie restriction can lead to increased cortisol levels, which increases inflammation and may result in symptoms such as weight gain, fatigue, and high blood pressure.

A note from Paloma

In summary, while the Sirtfood diet promotes the consumption of healthy foods, its extreme calorie restriction and potential for nutritional deficiencies raise concerns about its long-term sustainability and overall impact on health. There is also a lack of robust scientific evidence to support the diet’s claims.

Individuals considering this diet should be aware of these potential risks and consult with a healthcare professional before significantly changing their eating patterns. Many in the nutrition field advise approaching the Sirtfood diet with caution.

When you want to integrate nutrition into your overall approach to managing hypothyroidism, Paloma Health can cut through all the options and help you quickly find a balanced diet plan that works safely for you. Your Paloma team can include expert thyroid nutritionists to help you develop the best nutritional plan for your overall health and optimal thyroid support. Paloma’s nutritionists collaborate with practitioners to assess your nutritional status and tailor a plan that is optimal for your health. They can provide guidance, review food journals, and offer ongoing support to help you stick to your nutritional goals. You can access this support through virtual consultations, a 12-week nutrition program, and many other resources designed to provide personalized care and support for your thyroid journey.


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Mary Shomon

Patient Advocate

Mary Shomon is an internationally-recognized writer, award-winning patient advocate, health coach, and activist, and the New York Times bestselling author of 15 books on health and wellness, including the Thyroid Diet Revolution and Living Well With Hypothyroidism. On social media, Mary empowers and informs a community of more than a quarter million patients who have thyroid and hormonal health challenges.

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