Thyroid Diet Plan: A 7-Day Evidence-Based Menu

There is no diet that cures hypothyroidism, and no food replaces thyroid hormone replacement. What nutrition can do is supply the four nutrients thyroid hormone synthesis depends on — iodine, selenium, zinc and iron — avoid interference with medication absorption, and manage the weight, cholesterol and constipation that often accompany an underactive thyroid.

Free tool: Levothyroxine timing checker — enter your pill time and see the earliest safe time for coffee, food, calcium and iron.

⚠️ Medical disclaimer: Never adjust levothyroxine based on diet. Any change in food timing or iodine intake should be followed by repeat TSH testing at your clinician's direction.

Key takeaways

• Levothyroxine timing beats every food choice: empty stomach, 30–60 minutes before food, and 4 hours away from calcium, iron, and soy.
• Selenium 55–200 µg/day — 1–2 Brazil nuts covers it. Do not exceed 400 µg.
• Iodine 150 µg/day — both deficiency and excess cause hypothyroidism. More is not better.
• Goitrogens in cooked cruciferous vegetables are a non-issue at normal intakes.
• If your diagnosis is Hashimoto's (most hypothyroidism in iodine-sufficient countries), see the Hashimoto's diet plan.
• If your thyroid is overactive instead, the approach inverts — see the 40-day hyperthyroidism meal plan and Graves' disease diet.

Table of contents

1. The four critical nutrients
2. Levothyroxine and food timing
3. Goitrogens: the actual evidence
4. Foods to prioritise
5. Foods to limit
6. The 7-day thyroid meal plan
7. Weight, cholesterol and constipation
8. Supplements worth considering
9. FAQ
10. Sources

The four critical nutrients

Nutrient	Role	Adult target	Best sources
Iodine	Substrate for T4/T3	150 µg/day (220 pregnancy)	Iodised salt, seafood, dairy, eggs
Selenium	Cofactor for deiodinase (T4→T3) and glutathione peroxidase	55 µg/day (UL 400 µg)	Brazil nuts, tuna, sardines, eggs
Zinc	TSH signalling, T3 receptor function	8–11 mg/day	Oysters, beef, pumpkin seeds
Iron	Thyroid peroxidase is a haem enzyme	8 mg men / 18 mg women	Red meat, lentils, spinach + vitamin C

Iron deficiency is a frequently missed reason for persistent symptoms despite normal TSH. Ferritin below about 30 ng/mL is worth investigating even when haemoglobin is normal.

Selenium caution: a single Brazil nut can contain 68–91 µg. Two per day is plenty; a handful daily risks selenosis.

Levothyroxine and food timing

This is the highest-impact section of this article.

• Take levothyroxine on an empty stomach with water, 30–60 minutes before breakfast (or at bedtime, 3+ hours after eating — equally effective in trials).
• Separate by 4 hours: calcium supplements, iron supplements, magnesium, antacids, and high-dose soy isoflavones.
• Coffee within 60 minutes reduces absorption by up to 30%. Wait the hour.
• High-fibre meals and grapefruit can modestly reduce absorption — consistency matters more than avoidance.
• Keep the routine identical day to day so your dose is titrated against a stable pattern.

Goitrogens: the actual evidence

Cruciferous vegetables (broccoli, kale, cabbage, Brussels sprouts) contain glucosinolates that can theoretically inhibit iodine uptake. In practice:

• Cooking deactivates most goitrogenic compounds (steaming reduces them substantially).
• Clinically meaningful effects have been documented at extreme intakes — the well-known case report involved roughly 1–1.5 kg of raw bok choy daily.
• In iodine-sufficient people eating normal portions, no effect on thyroid function has been demonstrated.

Verdict: eat your cruciferous vegetables, mostly cooked. Do not build your diet around raw kale smoothies every day.

Soy is similar: a meta-analysis found soy does not affect thyroid hormones in euthyroid people, but it can increase levothyroxine requirements — so separate soy from the medication, do not eliminate it.

Foods to prioritise

• Fish and seafood — iodine, selenium, omega-3
• Eggs — iodine, selenium, protein
• Brazil nuts — 1–2 daily for selenium
• Dairy or fortified alternatives — iodine, calcium (away from medication)
• Iodised salt — the simplest iodine insurance
• Lean red meat and legumes — iron and zinc
• Fibre-rich vegetables, fruit, whole grains — constipation is a core hypothyroid symptom
• Adequate protein, 1.2–1.6 g/kg — supports the resting metabolic rate that hypothyroidism suppresses

Foods to limit

• Highly processed, high-sodium foods — worsen the fluid retention common in hypothyroidism.
• Excess iodine supplements, kelp and seaweed tablets — kelp can deliver several thousand micrograms per serving and precipitate thyroid dysfunction. This is a real and under-recognised harm.
• Alcohol in excess — associated with lower thyroid volume and hormone output.
• Added sugar and refined starch — not thyroid-specific, but hypothyroidism raises cardiometabolic risk. See the metabolic syndrome diet.

The 7-day thyroid meal plan

Take levothyroxine on waking; breakfast 60 minutes later.

Day 1 — B: scrambled eggs, spinach, rye toast · L: tuna salad with mixed greens and olive oil · D: baked cod, roast potatoes, steamed broccoli · S: 2 Brazil nuts

Day 2 — B: Greek yoghurt with berries and pumpkin seeds · L: lentil soup with wholegrain bread · D: grilled chicken thigh, quinoa, roasted carrots · S: apple with cheese

Day 3 — B: oats with milk, chia and banana · L: prawn and avocado salad · D: beef stir-fry with brown rice and mixed vegetables · S: 2 Brazil nuts

Day 4 — B: 2 boiled eggs, tomato, wholegrain toast · L: chickpea and roasted vegetable bowl · D: baked salmon, sweet potato, green beans · S: kefir

Day 5 — B: cottage cheese with peach and walnuts · L: leftover salmon on a large salad · D: turkey chilli with kidney beans and rice · S: 2 Brazil nuts

Day 6 — B: omelette with mushrooms and cheese · L: sardines on rye with cucumber salad · D: roast chicken, barley, steamed cabbage · S: orange and almonds

Day 7 — B: overnight oats with flaxseed and blueberries · L: egg and quinoa salad bowl · D: white fish tacos with slaw and black beans · S: dark chocolate and Brazil nuts

Weight, cholesterol and constipation

• Weight: untreated hypothyroidism lowers resting metabolic rate by roughly 10–15%. Once TSH is normalised, weight responds to the usual levers — protein, resistance training, calorie awareness. See Hashimoto's weight loss.
• Cholesterol: LDL often rises in hypothyroidism and improves with adequate replacement. Soluble fibre from oats and legumes helps further.
• Constipation: target 30 g fibre, 2 L fluid, and daily movement. Increase fibre gradually.

Scan any food in Nutrtion.io to see its iodine, selenium, zinc and iron content — and set medication reminders so you never take levothyroxine within an hour of coffee or calcium again.

FAQ

What foods should I avoid with an underactive thyroid? Excess iodine supplements and kelp, and anything taken within 4 hours of levothyroxine (calcium, iron, soy). Cooked cruciferous vegetables are fine.

Can diet cure hypothyroidism? No. Diet supports thyroid function and manages symptoms; it does not replace hormone therapy.

Should I take an iodine supplement? Only if a clinician confirms deficiency. Excess iodine can trigger or worsen thyroid dysfunction, especially in Hashimoto's.

Is gluten-free necessary? Only if you have coeliac disease, which is more common in autoimmune thyroid disease. See Hashimoto's gluten-free diet.

How long before diet changes show up in labs? Retest TSH 6–8 weeks after any consistent change in medication timing or iodine intake.

Can I drink coffee? Yes — just not within 60 minutes of your levothyroxine.

Sources

1. NIH Office of Dietary Supplements — Iodine, Selenium, Zinc, Iron fact sheets, 2024.
2. Jonklaas J, et al. Guidelines for the Treatment of Hypothyroidism (American Thyroid Association). Thyroid. 2014.
3. Benvenga S, et al. Altered intestinal absorption of L-thyroxine caused by coffee. Thyroid. 2008.
4. Messina M, Redmond G. Effects of soy protein and soybean isoflavones on thyroid function. Thyroid. 2006.
5. Winther KH, et al. Selenium in thyroid disorders — essential knowledge for clinicians. Nat Rev Endocrinol. 2020.

Free printable: Food Safety & Timing Guide (PDF) — thyroid and gut food evidence, the levothyroxine and supplement timing chart, a shopping checklist and a one-week symptom log.