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Underactive thyroid (hypothyroidism): Advice on nutrition and exercise

Underactive thyroid (hypothyroidism): Advice on nutrition and exercise

You eat incredibly healthily and wear yourself out in the gym. And yet there are no noticeable results.

Your story may look like this:

You eat 1,500 calories per day, you do strength training, cardio exercise in the form of interval training, you eat plenty of green vegetables and limit your carbohydrate intake – and yet you don’t lose any weight. Should you be eating even less? Exercising even more?

You also feel lethargic, tired and depressed. It may be your thyroid, which affects everything in your body as well as your weight (eating a halfway healthy diet and having the odd magical sweet craving is not part of the pathology). If you have an underactive thyroid, every single one of your bodily functions is going to be slower, including digestion, intestinal processing and metabolism.

In section 1 about hormones, I wrote about how you can check (based on symptoms) whether you suffer from hypo or Hashimoto’s thyroiditis.

But if you are physically active – i.e. your lifestyle involves a fitness regime with everything that entails – it can be even more frustrating as you won’t be seeing any progress happening at all.

Does that sound familiar?

  • You count calories and exercise several times a week but don’t lose any fat
  • You lose 10 kg but put those 10 kg back on over and over again over a period of years
  • Your energy level is low, and you are irritable
  • Sex life … what sex life?

Before I go any further, I want to point out an important fact: less food and even more exercise are never going to be a solution to your problem.

So, are you overweight because you eat too much, are you lazy, or is it your thyroid?

Bearing in mind that many of the thyroid’s functions are related to the typical image of overweight that we have today, it’s not unusual for many trainers (and dietitians) to treat the problem as their client simply being overweight and perhaps not always believe that their client with hypo is taking care of themselves. It’s not at all unusual for women who are overweight and have hypo to feel a failure – that they’re not trying hard enough. The fact is that much of the advice you read in health magazines may do more harm than good to those who are suffering from hypo or a slow metabolism.

Examples of activities that are NOT a good idea:

Cardio and an excessive amount of exercise Cardio has become an extremely popular way of burning fat and sometimes it is used as though it were the only way. But as has been shown, cardio is not actually great at burning calories. Not only that. Too much cardio is a sure way of slowing down your metabolism further and increasing the stress hormone cortisol. If you have hypo, you should be very careful about how much cardio you do (and how much you exercise generally). If you jog a lot, this will certainly impact negatively on your thyroid. Exercising like mad is the last thing you should do.

Low calorie intake Reducing the amount you eat is the most certain way of slowing down your metabolism. If you ask me, if you suffer from hypo, that is something that should be absolutely forbidden.

Low carb diet Reducing your carb intake every now and then is fine, but constantly keeping your carb intake low will make your metabolism slower and, if you suffer from hypo, following that kind of diet is really not good for you.

If you do the above for years, you will create a situation where you are hardly eating anything and you’re doing a huge amount of exercise every day – but your body is still not going to be particularly effective at burning fat.

Most people who want to accelerate their fat burning operate the strategy that goes: ‘eat less and exercise more’. With time, the body is going to learn to function on a small number of calories. A new study published recently found that the participants in ‘The Biggest Loser’ had a dramatically slower metabolism after the programme than before the show. Their daily burning had stalled, and they were burning 500 fewer calories than they had done before the show. The study also found that over 90% of the participants put all the weight that they had lost back on.

Why? Because you got your body used to burning 1,500 calories, not 2,000 (which you might perhaps want to eat now).

And then you read that exercise can boost your metabolism … But considering how much exercise the participants in ‘The Biggest Loser’ do (I know, since I took part in 2012) and how little they eat, the effect is the exact opposite!

It’s not even unusual for ‘regular’ health-conscious people who are a few kilos overweight because the method behind it is the same: a lot of exercise and little food, even if the food is the best food. When you go for low calorie intake, you will lose fat, for sure … but only in the beginning. Then the body’s defence mechanism kicks in.

So, what is the solution?

The solution is not as simple as ‘eating less and exercising more’.

The real solution for countering a slow metabolism is:

  1. Stop doing cardio. Completely. At least to get your stress levels down to begin with.
  2. Start eating more.
  3. Eat more carbs (if you were eating a low carb diet).
  4. Do more effective exercise such as strength training.

As you can see, my advice is quite the opposite of what you may have heard before, but I hope you understand why I think the way I do – it’s simply because that’s how the body WORKS. You just need to check and analyse how you eat and exercise today.

If you do everything right, you will get the results you always wanted to achieve with this strategy. For many of you, this is actually the only way. Your only solution is to train your body back to being able to function on a higher calorie intake, replace cardio with different exercise that is more effective and boost your metabolism with the help of a diet that is dense in nutrients.

Photo iStockphoto
Sources: Davidson MB, Chopra IJ. Effect of carbohydrate and noncarbohydrate sources of calories on plasma 3,5,3-triiodothyronine concentrations in man. Journal of Clinical Endocrinology & Metabolism, Apr. 1979; 48 (4): 577–581.

Fery F, et al. Hormonal and metabolic changes induced by an isocaloric isoproteinic ketogenic diet in healthy subjects. Diabetes & Metabolism, Dec 1982; 8 (4): 299–305

Updated December 10, 2021

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