Can keto cause thyroid issues?

If you're doing something called the healthy version of a ketogenic diet your thyroid is not going to be a problem. In fact, you're going to be more efficient to the point where the thyroid doesn't have to work so hard. And you may even not need as many of those thyroid hormones to have everything work. You may see a little bit of a lowering of like T4 or even T3, but it'll be within normal range. The thing that people diagnose hypothyroidism with is something called the thyroid stimulating hormone. That's a pituitary hormone. That will always just stay normal. So nothing to worry about. You're just eating healthy foods with low carbs.