The Best Low Carb Diet for Thyroid Patients: A Complete Guide

Should you go low-carb if you have a thyroid problem? It’s not as straightforward as you might think.

The short answer? Sometimes.

The longer answers? It depends.

It turns out that your thyroid needs carbs to function optimally, which is why I generally recommend at least 100 grams of high-quality whole food carbohydrates each day.

But… and this is a big but, if you already have pre-existing insulin resistance (which a lot of thyroid patients do), then it makes sense to go low carb for a short period of time to get that under control.

And if you do, here’s how you want to do it:

The Basics

Eat: Meat, fish, eggs, vegetables growing above ground, and natural fats (like butter, coconut oil, avocado oil, olive oil, and full-fat dairy products)

Don’t eat: Sugar, starchy foods (pasta, rice, beans, and potatoes), refined carbohydrates (bread, pasta, bagels, cereals), and processed oils (corn, cottonseed, soybean, safflower, sunflower oil)

Eat when you are hungry and until you feel satisfied. There is no need to count calories or weigh your food. Focus on eating real, whole foods with single ingredients. Avoid food with more than 3 ingredients on the label!

You should practice the ‘eyeball’ test. That is, look at food with your eye and you should easily be able to determine if the food is real or if it was processed in a factory (examples: boxed potatoes versus real potatoes – very easy!).

Eat all you like
PROTEIN	Poultry: Chicken, turkey, duck, pheasant, cornish game hen (look for hormone and antibiotic-free whenever possible)   Seafood: Wild salmon (canned, fresh or frozen), small halibut, scallops, shrimp, anchovies, clams, cod, crab, flounder, herring, mussels, sardines, trout Eggs: 3 per day (choose organic, free-range eggs whenever possible) Red or wild meat: Lamb, beef, bison, venison, ostrich, deer, elk Soy: tofu or tempeh (organic, non-GMO only) Nuts and seeds: Nuts: almonds, brazil, cashews, hazelnuts, macadamia, pecans, pine, pistachios, walnuts, raw cacao Seeds: chia, flax, hemp, pumpkin, sesame, sunflower Nut/seed butters: almond, cashew, pecan, macadamia, walnut Nut flours: almond meal, coconut flour
FAT	Oils: for cooking with high heat: coconut, grapeseed, avocado for looking with moderate heat: olive, grape seed, unrefined sesame for cooking without heat: flaxseed, extra virgin olive oil Nuts and seeds: see aboveFish: Salmon (canned, fresh, or frozen), sardines, trout, herring, anchoviesProduce: avocado, olives, raw cacao, coconut
NON- STARCHY VEGETABLES	Artichokes, arugula, asparagus, avocado, bean sprouts, beet greens, broccoli, brussels sprouts, cabbage, cauliflower, celery, chives, collard greens, cucumber, dandelion greens, eggplant, endive, garlic, ginger root, green beans, hearts of palm, kale, kohlrabi, lettuce, mushrooms, mustard greens, onions, parsley, peppers (bell, chili, etc.), radicchio, radish, rutabaga, seaweed, shallots, snap beans, snow peas, spinach, summer squash, swiss chard, tomatillos, tomatoes, turnips, turnip greens, watercress, zucchini At least 1 cup of brassica-based vegetables per day: cabbage, broccoli, cauliflower, arugula, bok choy, Brussels sprouts, kale
DAIRY PRODUCTS	If you tolerate dairy and do not have other active medical conditions (Small intestinal bacterial overgrowth, yeast overgrowth, intestinal dysbiosis, multiple food allergies) enjoy full-fat options like real butter (from grass-fed cows), sour cream, greek/Turkish yogurt, and high-fat cheeses. Avoid regular milk and/or skim milk as they contain lots of milk sugar and may be loaded with hormones that disrupt your endocrine system. Avoid low-fat dairy products with high sugar (flavored yogurts, etc.) Milk alternatives include: unsweetened/full-fat coconut milk, unsweetened almond milk

AVOID these foods
SUGAR	This will halt your weight loss in its tracks. Especially avoid soft drinks/soda, candy, juice (apple juice, orange juice, etc.), sports drinks (Gatorade, Powerade, etc.), chocolate, cakes, pastries, ice cream, breakfast cereals, and artificial sweeteners.
STARCH	Bread, pasta, rice, potatoes, french fries, potato chips, porridge, oatmeal, etc. Whole grain or whole wheat products are still bad! Avoid legumes (beans and lentils) in the beginning, though you may be able to add these and root vegetables back in moderation (potatoes, sweet potatoes) when you achieve your goal weight.
MARGARINE	Incredibly unhealthy and pro-inflammatory in high doses, very high in omega-6 fatty acids.
BEER	Think of this as liquid bread – lots of rapidly absorbed carbohydrates that lead to insulin resistance.

Eat Occasionally
DARK CHOCOLATE	Dark chocolate: Always at least 70% cocoa and limit serving to 1-2 ounces. The darker the chocolate the more health benefits.
FRUIT	Blackberries, blueberries, cranberries, kiwi, lemons, raspberries. These fruits are jam-packed with antioxidants and have significantly less sugar per serving than other fruit. Note that some people are very sensitive to fructose in fruit, monitor your fruit intake carefully and eat it as a treat.   Aim for ½ cup daily of berries

Drinks and liquids
Preferred liquids	Water: Aim for 1 gallon per day, minimum of 64 ounces/day. Tea: All kinds of teas with caffeine or without are great for health. If cutting back on coffee try yerba mate, green tea, or black tea. Coffee: 3-5 cups per day, consume with full-fat products (heavy cream, full-fat coconut milk). Try bulletproof coffee with grass-fed butter, coconut/MCT oil, and liquid stevia.

Recommended Portion sizes and servings per day for optimal results
	Portion size	Servings per day
Protein	4-6 ounces	3 daily, plus more with snacks
Fruit	½ cup of berries	once per day
Nuts or seeds	1-2 handfuls	once per day
Nut butter	1-2 tablespoons	once per day
Non-starchy vegetables	½ cup cooked or 2 cups raw	5-7 servings minimum
Healthy fats and oils	1 tablespoon of oil, ¼ cup of high-fat fruits (olives and avocado)	3-8 per day
Tea	4-6 ounces	1-2 per day
Water	8 ounces	8 cups minimum, more if exercising/detoxing or taking with supplements

A quick note: you may have heard that brassica vegetables (broccoli, kale, cauliflower) are bad for your thyroid because they contain goitrogens. In most cases, this is not something you need to worry about as long as you are cooking them. Cooking significantly reduces goitrogenic activity. The nutritional benefits far outweigh the risk.

If you have Hashimoto’s, pay extra attention to dairy. Many autoimmune patients have a sensitivity to dairy proteins (casein and whey) that can increase intestinal inflammation. If you notice bloating, joint pain, or fatigue after consuming dairy, consider eliminating it for 30 days and see how you feel.

Answers to Common Questions About Low-Carb Diets for Thyroid Patients

How Does a Low-Carb, High-Fat Diet Work for Thyroid Weight Loss?

A: Diets high in refined carbohydrates (bread, pasta, oats, grains, etc.) and sugars cause increases in the hormone insulin (refer to the interplay of hormones and obesity). Unfortunately, any trace of insulin – even one slice of bread worth- will completely shut down fat burning as a source of fuel in your body.

When you have sustained levels of insulin, otherwise known as insulin resistance, your body never gets the chance to burn fat for fuel. Instead, it is reliant upon sugar and glucose as its primary energy source.

Your entire body can only hold about 2,000 calories in the form of sugar or glucose. Compare that to fat, which even an average person carries close to 100,000 calories! The cruel joke is that when eating diets high in carbohydrates, your biochemistry doesn’t allow your body to use any of those fat calories, and instead, it is reliant upon sugar and glucose.

This reliance on sugar, combined with the relatively low supply of calories in your body stored as sugar, causes massive swings in blood sugar throughout the day. These changes in blood sugar cause irritability, fatigue, lethargy, and a constant need for snacking and eating.

Foods high in healthy fat do not cause an increase in insulin and thus lead to very constant and controlled blood sugar. It also changes your biochemistry and ‘unlocks’ the fat stores in your body as a source of energy.

This is why this approach works so well when your metabolism is already sluggish. If your body is holding onto fat more stubbornly than it should, addressing the insulin side of the equation lets your medication do its job more effectively.

How Much Fat Do You Need?

A: When following the high-fat, low-carbohydrate diet, there are some potential pitfalls that can really curb your weight loss. One of those is not eating enough fat. The other is eating too much protein in its place.

Many people think that following a low-carbohydrate diet means you just eat meat all day without any bread. While meat is fine, you can’t forget the healthy fats!

In fact, healthy fats should total about 70 percent of your total calories…

Eating this much fat can sometimes make people nervous. They think that eating fat will cause them to get fat.

Eating fat will NOT cause you to get fat…

Eating too many carbohydrates makes you fat because of insulin. Insulin turns glucose and sugar straight into fat.

Several studies show that eating fat causes you to lose weight. (2)  These studies also show that high-fat diets are superior to low-fat, calorie-restricted diets both in the amount of weight loss and in how the weight loss changes other risk factors for heart disease and diabetes.

The best part is this: you don’t have to restrict the amount you eat to lose weight either. Once you change your biochemistry and your internal thermostat, your body burns fat as fuel, and weight loss becomes effortless.

Fat is also important because many fat-soluble vitamins (A, D, E, K) play a direct role in immune regulation and hormone production. If you’re eating low-fat, you may not be absorbing these nutrients well, even if you’re supplementing.

How do you add more fat to your diet?

1. Start cooking with fats (coconut oil, olive oil, grass-fed butter). Add it to your recipes in place of things like canola oil. Coat your pans with healthy fats and then add them on top of your food after you’re done! There are plenty of high-fat sauces that taste amazing that go on top of vegetables, steak, chicken, etc.
2. Start making your own salad dressings.
3. Add nuts to your diet. 1-2 tablespoons of nut butter per day or a handful of healthy nuts.
4. Eat high-fat dairy products. Make whipping cream out of heavy cream and add it to blueberries or strawberries. Drink whole milk.
5. Add fish to your menu 2-3x per week.
6. Add avocados and olives to your dishes.
7. Look on Google for more high-fat, low-carbohydrate recipes.

Are All Carbohydrates Bad for Me?

Carbohydrates from all sources are NOT created equal. When I refer to carbohydrates and sugar, these terms are often used interchangeably when they really are two different animals.

Carbohydrates are broken down into sugars after they are consumed, and so most people don’t differentiate between the two for this reason.

The takeaway point here is that certain carbohydrates (made up of many sugar molecules) are broken down into sugar at slower or faster RATES depending on several factors. When you slow down the rate at which they are broken down, you slow down the rate at which they are absorbed. This is important because the absorption rate is what determines the amount of insulin that is released.

Slow absorption = slower insulin response = no weight gain

Rapid absorption = insulin spike = belly fat

So, the question really is this – what carbohydrates are slowly absorbed?

The answer is natural, whole foods that are high in fiber. Think of vegetables, fruit, potatoes, sweet potatoes, carrots, and beans of all kinds.

When you consume natural whole foods that are both high in fiber and high in carbohydrates (like those listed above), you slowly absorb them and do not spike your insulin levels, and do not trigger the negative cascade of events that are caused by other high carbohydrate/low fiber foods (bread, cereals, pasta, rice, soda, etc.).

A word of caution: It is best to stay away from starchy foods while you are trying to lose weight.

If you are overweight, to begin with, then we know you already have some degree of insulin resistance. For this reason, it’s best to reintroduce starchy foods AFTER you have sensitized your body to insulin with a low-carbohydrate diet in conjunction with intermittent fasting.

Don’t reintroduce healthy carbohydrates into your diet until you are at your goal weight.

One important caveat if you have hypothyroidism: don’t go too low for too long. Your body needs some carbohydrates to convert T4 into active T3. If you stay below 50 grams for extended periods, you may see your T3 levels drop and your reverse T3 climb. That’s why I recommend a moderate approach (50-75 grams) rather than full keto.

Will I Be Hungry Without Carbs?

The short answer: No.

The long answer: Well, maybe for 3-4 days…

…It turns out that your appetite control hormones also get confused when you become insulin-resistant. (3)

If you are like most people, you are probably living in a state where it’s difficult to think about going 12 hours without food. This constant sensation of hunger is triggered by low blood sugar, but also because your brain isn’t getting the right signals – when you’re hungry or when it’s time to stop eating.

Much like your body gets resistant to insulin, so too does it get resistant to leptin.

By eating a low-carbohydrate, high-fat diet, you reset those signals in your brain. Not only this, but high-fat foods are more satiating than even carbohydrates…

Consider this real-life example:

Imagine a scenario where you are given the option between unlimited blueberry pancakes or unlimited pork chops.

You always seem to have room for 1 more pancake, even though you are stuffed to the brim. This isn’t true with the pork chops, though. Once you have a couple, the thought of another almost makes you sick.

The reason for this feeling is the fat content of the food.

Your body actually prefers to burn fat when it can. Fat is a more metabolically efficient molecule than glucose in terms of what your body can do with it. Fat on a per-molecule basis turns into much more energy than glucose.

This is why counting calories and weighing food don’t matter anymore. You simply eat until you feel full and satisfied and let your body do the rest.

On a high-fat diet, you will enjoy controlled blood sugar levels and a more sustained feeling of energy. You won’t find yourself slowing down in the mid-afternoon, looking for a sugary beverage with caffeine to kick you into gear. Your blood sugar and energy levels stay constant and consistent.

When you understand the biology of obesity and metabolism, you can more easily “hack” into your body’s chemistry to get long-lasting, amazing results. This diet is very doable because you literally get to eat highly palatable, nutritious foods.

If you’ve been dealing with constant hunger that seems out of proportion to what you’re eating, leptin resistance is likely part of the problem. A high-fat diet helps reset those signals faster than almost any other intervention I’ve seen in my practice.

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Will Low Carb Make My Cholesterol Worse?

If you eat more fat, especially saturated fat and cholesterol, wouldn’t that increase your blood lipid levels and put you at increased risk for a heart attack? This couldn’t be farther from the truth.

This mindset and way of thinking represent the last 40 years of fat fear that was based on little evidence.

Keep in mind that hypothyroidism itself causes elevated LDL and total cholesterol. Many patients get put on statins when the real fix is optimizing their medication. If your cholesterol improves on this diet AND your labs are dialed in, that’s a sign your metabolism is heading in the right direction.

Will I Experience Side Effects in the Beginning?

When you stop eating sugar and refined carbohydrates, you may experience some side effects as your body adapts to burning fat instead of sugar for fuel. These side effects have been referred to as the “low-carb flu”.

Despite this name, they tend to be quite mild, and even then, they can be decreased with some easy interventions.

Some of these symptoms include:

1. Headache
2. Increase in appetite with food cravings
3. Irritability
4. Fatigue
5. Brain fog, Dizziness/lightheadedness

These side effects only last about 3-5 days and can be decreased by drinking plenty of fluids and taking in plenty of minerals. Predominantly, you want to increase your salt intake by taking salt tabs, and by drinking 1-2 cups of broth per day, or by adding extra salt to your meals.

Insulin acts on the kidneys to cause water and mineral retention. When you reduce insulin and carbohydrates, your kidneys tend to “spill” out more of these minerals. It doesn’t take long for your body to figure out what’s going on, though, and make changes.

You may notice these symptoms more intensely if your metabolism is already running slow, especially fatigue and brain fog. Be patient with yourself. If side effects persist beyond a week, check in with your doctor. Changes in diet can sometimes shift how you absorb or metabolize medication.

You can also try getting prescription medication for an appetite suppressant from your doctor to help you get through this time period if you are having trouble. Phentermine works well for this.

How Low Should You Go?

Low-carbohydrate diets can vary in range from < 10 grams per day total to < 100 grams per day. In the beginning, I recommend eating enough carbohydrates to allow the inclusion of vegetables and fruit (on occasion).

In general, the lower your carbohydrate intake, the faster you will lose weight.

At the beginning of your journey, it is, therefore, better to reduce carbohydrates to the range of 50-75 grams per day, which is made up of real whole foods and primarily vegetables and fruits.

Maintaining a low-carbohydrate diet that induces ketosis (typically carbohydrate programs < 10 grams per day) can be beneficial for certain health conditions, including Alzheimer’s, multiple sclerosis, epilepsy, cancer, and Parkinson’s. This type of program works by inducing the production of ketone bodies that act as a completely different energy source in the brain.

I don’t necessarily recommend this diet for everyone unless you have a medical condition where it would be helpful. That doesn’t necessarily mean you should be afraid of ketosis; in fact, this is something that you should aim for on your fasting days, but it doesn’t mean you have to be in it 24/7.

Be cautious with very low-carb and ketogenic diets if you have hypothyroidism. The T4-to-T3 conversion process requires some insulin, and if you drop it too low for too long, your active hormone levels can suffer. A moderate approach works better for most of my patients.

My recommendations:

• 50-75 grams of carbohydrates per day in the form of real, whole vegetables and fruits
• Increase healthy sources of carbohydrates, such as potatoes/sweet potatoes/wild rice, etc., when your target weight has been achieved

How Long Can You Stay Low Carb?

You can stay on this diet indefinitely with some minor tweaks over time. Once your weight loss has been achieved, you can slowly add in healthy starches in the form of whole foods like red and wild rice, potatoes, sweet potatoes, and beans.

That said, monitor your labs more closely than the average person while doing low carb. I recommend checking free T3, free T4, and reverse T3 every 6-8 weeks while you’re actively losing weight. If your free T3 starts dropping or reverse T3 starts climbing, it’s time to increase carbs slightly or adjust your medication.

What About My Other Health Problems?

As a bonus, you will likely find that many other health problems you have will improve or completely resolve.

Think of food as information. Information both for your gut bacteria and for your genes. When you cut out the bad information (sugar, grains, etc.) your body starts to turn on genes that protect you from chronic health problems such as diabetes, hypertension, hyperlipidemia, and cancer.

In addition, this diet will also promote changes in your gut bacteria to support healthy bacteria that regulate your immune system and hormonal balance. It’s not a coincidence that I include lifestyle changes in this program (stress reduction, sleep patterns, and hormonal testing), because everything in the body is so well connected.

This is especially true if you have an autoimmune condition like Hashimoto’s. Gut health directly impacts autoimmune activity. When you clean up your diet, you reduce the inflammatory triggers that can cause your immune system to attack your own gland. Many of my patients see their antibodies decrease after making these changes.

Now it’s your turn… do you have experience eating a low-carbohydrate high-fat diet? What kinds of results did you get?

References and citations:

(1)  Gardner, Christopher D et al. “Comparison of the Atkins, Zone, Ornish, and LEARN diets for change in weight and related risk factors among overweight premenopausal women: the A TO Z Weight Loss Study: a randomized trial.” Jama 297.9 (2007): 969-977.

(2)  Volek, Jeff et al. “Comparison of energy-restricted very low-carbohydrate and low-fat diets on weight loss and body composition in overweight men and women.” Nutr Metab (Lond) 1.1 (2004): 13.

(3) Nazarians-Armavil, Anaies, Jonathan A Menchella, and Denise D Belsham. “Cellular insulin resistance disrupts leptin-mediated control of neuronal signaling and transcription.” Molecular Endocrinology 27.6 (2013): 990-1003.