Hypothyroidism and weight: what to eat (and what to avoid)

Why losing weight is harder

The thyroid is the thermostat of your metabolism. When it produces little hormone (hypothyroidism), your body spends less energy at rest, retains more water and symptoms appear such as tiredness, feeling cold and constipation. All of that translates into weight gain being easier and loss being slower. But be careful with the interpretation: it is not that the fat is "impossible to remove", it is that your expenditure is reduced. And that has a solution on two fronts: medical treatment, which comes first, and food and exercise, which add up.

What to prioritise on your plate

Beyond covering the thyroid-specific nutrients, the base is a filling and anti-inflammatory way of eating:

• Iodine: fish, seafood, dairy, eggs and iodised salt. Essential to make thyroid hormone.
• Selenium: Brazil nuts (1-2 a day are enough), fish, eggs, legumes. Supports hormone conversion.
• Protein at every meal: it fills you up and protects your muscle mass.
• Plenty of fibre: vegetables, legumes, wholegrains and fruit — they help with constipation, common in hypothyroidism.
• Healthy fats and anti-inflammatory foods: olive oil, oily fish, berries.

What to watch (without obsessing)

There is no long list of forbidden foods, but there are some nuances. It is wise not to overdo ultra-processed foods (as in any diet) and not to eat large amounts of RAW cruciferous vegetables (cabbage, broccoli, cauliflower) very regularly, because in excess and raw they can interfere with the thyroid; cooked, that effect disappears and they are healthy. The same with soy in large amounts. And very important: keep levothyroxine away from coffee, calcium and iron, which reduce its absorption.

Muscle is your ally

If your metabolism is low because of the thyroid, the best long-term investment is building muscle, because it is the tissue that burns the most energy at rest. Strength training, 2-3 times a week, raises your expenditure in a lasting way, counters part of the metabolic brake and improves body composition. Combine it with a MODERATE deficit (no extreme diets, which can also affect the thyroid more) and patience: results come, just at their own pace.

Before changing anything

Hypothyroidism is a medical diagnosis controlled with blood tests (TSH, T4) and treatment. Food helps, but does not replace the medication or the follow-up. If you suspect your thyroid is not well controlled — a lot of tiredness, feeling cold, hair loss, weight stalling despite doing everything right — ask your doctor to check your levels. Food is a useful lever within a plan worth supervising.