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How Many Calories Should I Eat With Hypothyroidism?

Calories & macros: finding the best approach if you have hypothyroidism.

This is the formula I use to find baseline calorie intake and macronutrient ratios for my hypothyroid patients. I also answer questions about whether or not intermittent fasting, time-restricted eating, and cutting calories are “bad” for your thyroid.

Video Transcript

Today we’re talking about calories, macros, and hypothyroidism. Somebody asked the question: how many calories should they be eating? Can they be in a calorie deficit if they have hypothyroidism

Typically, the way your physiology should work, when you have a healthy metabolism, good thyroid physiology — not just by the gland, but you have enough thyroid hormone in the bloodstream, and you have good conversion at the cell level — is this: When you eat excess calories, as they’re being stored in your fat cells, they should send signals to your brain. One of the hormones, leptin, should tell your brain: you’re good, you’re satisfied, you don’t need to eat anymore. And that leptin should increase the conversion of T4 to T3, and tell the hypothalamus to drive the sympathetic nervous system to help burn off some of those excess calories. That’s how it should work.


But if you’re in a calorie deficit short term, then what the body will do is it might slow down the metabolism a little bit, but more than likely, it’s gonna just pull stored fat out of reserve and burn that as fuel.

If you’re in a chronic caloric deficit, then I think you’re gonna have a more significant impact on your thyroid physiology, and that could be a cell stressor. I mean, we see that in areas of famine where thyroid physiology is downregulated pretty significantly.

But I think for the average person, if it’s a day, two days, three days of a caloric deficit, as long as it’s not too severe, it’s not gonna have a significant impact on your thyroid physiology.

Now, there is this other discussion that intermittent fasting is bad because when you do time-restricted eating or intermittent fasting, it can lower your T3 levels. But part of the reason for that is that you’re liberating more stored calories from fat. And when you’re burning fat, one gram of fat generates nine calories. So that means you don’t need as much thyroid hormone to essentially drive energy production when you’re burning fat as a primary fuel.

So if you’re more of a low-carb ketogenic, intermittent type fasting type person, your T3 levels might be a little bit lower than the person who is a more carb-driven type consumer and uses more carbohydrates as their primary fuel source.

Okay, so how do you figure out what your calories should be? There are plenty of online calculators that you can use. I think your functional medicine practitioner can work with you to try and figure out where you should be. The calories you consume should really be based on height, weight, activity level, age, sex; a number of factors go into it. But I want to give you a simple calculation to kind of use to figure out what your total calories should be and then what your macros might look like.

We’ll start with figuring out what your protein intake should be. I typically use the formula: one gram of protein per pound of body weight. I weigh between 175 and 180 pounds, so my protein intake is somewhere between 175 and 180 grams of protein per day, on average.

The other way you can figure this out that’s based on the scientific literature is with your height, in centimeters. So I’m five foot nine, which is 175 centimeters. So 175 centimeters would correspond to 175 grams of protein per day, which is close to what that number would be based on my body weight.

So now that we have that 175 grams of protein, then we can use that as one of our calculations to get to our caloric load. I typically like to see somebody have protein be about 40% of their total calories. So if I’ve got 175 grams of protein multiplied by 4 calories for every gram of protein, that means 700 calories are gonna come from protein. Now, as I said, 40% of my caloric intake should be from protein. So to find your overall calories, take your protein and divide it by 0.4: 700 divided by 0.4 (40%) equals about 1,750 calories per day for me.

Now, somebody might argue it should be higher or lower, but that’s just a baseline number. My overall calorie intake would be based more on what my demands are, physical activity levels, etc.

Now I want to figure out the rest of my macros.

I like carbs to be about 30% of caloric intake, and fat to be about 30%. So that gets me to a hundred percent of my calories.

So now for the calculations:

Carbs: 1,750 * 0.3 = 525 calories of carbs per day. Divided by 4 calories per gram of carbohydrate = 131 grams of carbohydrate per day.

Fats: 1,750 * 0.3 = 525 calories of fat per day. Divided by 9 calories per gram of fat = 58 grams of healthy fats per day.

Now, if you’re a person who’s got tissue hypothyroidism going on despite taking thyroid medications, your T4 to T3 conversion is low, then I think it’s okay to be in about a 10 to 20% calorie deficit if you have extra body weight that you wanna reduce. However, I don’t recommend more than that unless you’re morbidly obese.

But if you just have an extra 15, 20, or 30 pounds of body weight that you wanna lose, I think that a 10% to 20% calorie deficit is probably a good place to be. Is this perfect for you? I don’t know, but this is gonna give you a good calculation of where to be.

Remember, if you have low T4 to T3 conversion, you probably don’t need as many calories as you think you do. You’re already storing those calories because your mitochondria aren’t making energy efficiently due to inflammation, infections, disrupted sleep patterns, and emotional stress — some excessive cell stress is downregulating the metabolism to begin with. So giving you sufficient calories to support optimal metabolism when you don’t have optimal metabolism is probably going to result in some weight storage.

So if you wanna burn excess calories, you don’t need to do huge calorie deficits for long periods of time (50% or more of calorie deficit). I think what you do is keep it simple, keep it low (10 to 20% calorie deficit), and then get to work on what’s causing the reduced T4 to T3 conversion.

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Hi, I’m Dr. Eric Balcavage, owner and founder of Rejuvagen. If you’re struggling with health issues or have questions, let’s chat. You can schedule a 15-minute call with me to get started.