More men in their late 30s and 40s are eating less meat, some for their heart, some for their budget, some because they grew up vegetarian. The usual worry is simple: can you still build muscle and stay strong on plants?
Yes, if you plan it. This guide covers what the research says about heart and metabolic health, how to build muscle without meat, and a sample day that hits about 140 g of protein.
Key takeaways
- Quality beats the label. Plant-based diets built on whole grains, legumes, nuts, fruit and vegetables are linked to lower heart disease risk. Diets heavy in refined grains, sweets and sugary drinks are linked to higher risk.
- You can build muscle on plants. With protein matched at 1.6 g/kg a day, vegans and meat eaters gained similar muscle and strength over 12 weeks.
- Eat a bit more protein and mix sources. Plant proteins are usually lower in leucine and slightly less digestible.
- Soy does not lower testosterone. A meta-analysis of 41 clinical studies found no effect in men.
- Watch six nutrients: B12, iron, zinc, omega-3s, vitamin D and iodine.
What plant-based, vegetarian and vegan mean
- Plant-based: a pattern built mostly on plants that may still include some meat, fish, eggs or dairy.
- Lacto-ovo vegetarian: no meat, poultry or fish, but dairy and eggs are in. The easiest pattern for high protein targets.
- Lacto-vegetarian: dairy yes, eggs no. Common in many Indian households.
- Vegan: no animal foods at all. Workable for muscle, but it needs the most planning.
The Academy of Nutrition and Dietetics states that appropriately planned vegetarian and vegan diets are healthful and nutritionally adequate, including for older adults and athletes. Note the words “appropriately planned.” White rice, fried snacks and sweet chai are technically vegetarian, but that is not what the research supports.
Heart and metabolic health: what the cohorts show
Most long-term evidence comes from large observational studies that follow people for decades. They cannot prove cause and effect, but they show consistent patterns.
Healthy versus unhealthy plant-based diets
Harvard researchers built scores to rate eating patterns. The healthful plant-based diet index (hPDI) rewards whole grains, fruit, vegetables, nuts, legumes, vegetable oils and tea or coffee, and scores refined plant foods and animal foods negatively. The unhealthful version (uPDI) rewards refined grains, potatoes and fries, sweets, juices and sugary drinks.
In a 2017 analysis of more than 200,000 US health professionals, including over 43,000 men, people with the highest hPDI scores had about 25% lower risk of coronary heart disease than those with the lowest. The highest uPDI scores were linked to about 32% higher risk. A 2016 analysis of the same cohorts found a similar pattern for type 2 diabetes: about 34% lower risk for the healthful version and about 16% higher risk for the unhealthful one.
The lesson: cutting meat is not the win by itself. Replacing it with dal, beans, whole grains, nuts and vegetables is. Replacing it with refined carbs and sugar can leave you worse off.
The EPIC-Oxford picture
The UK’s EPIC-Oxford study followed about 48,000 people for an average of 18 years. Vegetarians had about 22% lower risk of ischaemic heart disease than meat eaters, roughly 10 fewer cases per 1,000 people over 10 years. They also had about 20% higher stroke risk, mostly haemorrhagic stroke, roughly 3 more cases per 1,000 over 10 years. The reason is unclear, which is a reminder that a vegetarian diet still needs to be well rounded and blood pressure checks still matter.
| Study | Who was studied | Main finding |
|---|---|---|
| Satija et al., 2017 | 200,000+ US health professionals | Healthful plant-based diet: ~25% lower heart disease risk. Unhealthful: ~32% higher. |
| Satija et al., 2016 | Same cohorts, 20+ years | Healthful: ~34% lower type 2 diabetes risk. Unhealthful: ~16% higher. |
| Tong et al., 2019 | ~48,000 UK adults, 18 years | Vegetarians: ~22% lower heart disease risk, ~20% higher stroke risk. |
Building muscle on plants
After 35 you are already dealing with slower recovery and gradual muscle loss. So do plant proteins hold up?
The trial evidence
In a 2021 Sports Medicine study, young adult vegans and omnivores did 12 weeks of resistance training while eating 1.6 g of protein per kg of body weight a day, topped up with soy protein for vegans and whey for omnivores. Gains in muscle mass and strength were the same.
A 2018 meta-analysis of nine randomised trials, mostly in men aged 18 to 70, agreed: soy and animal protein supplements produced similar strength and lean mass gains with training. One caveat is that much of this research used younger adults, and older muscle responds less to protein. That is a reason to give yourself a margin.
Why plant protein needs a little help
A 2015 review in the Journal of Nutrition explained why plant proteins can produce a smaller muscle-building response per gram:
- They are often slightly less digestible.
- Most contain less leucine, the amino acid that acts as the main switch for muscle protein synthesis.
- Some are low in specific essential amino acids, such as lysine in grains and methionine in legumes.
The practical fixes are to eat more plant protein and blend sources. You do not have to combine them at every meal; variety across the day covers your needs. Classic pairings like dal with rice or roti, and beans with arepa or rice, already do the work.
How much protein to aim for
A 2018 meta-analysis of 49 trials found that extra protein stopped adding muscle at around 1.6 g/kg a day for most people, and the benefit was smaller with age. On a plant-heavy diet, aiming for about 1.6 to 2.0 g/kg, split across three to five meals, is a sensible target. For an 80 kg man that is roughly 130 to 160 g. See our guides to how much protein you need after 35 and the best muscle-building foods.
| Protein source | Strengths | Watch-outs |
|---|---|---|
| Dairy (milk, curd, Greek yogurt, paneer, queso fresco) | High quality, rich in leucine | Paneer and full-fat cheese are calorie-dense |
| Eggs | Complete protein, cheap, quick | Not eaten by all vegetarians |
| Soy (tofu, tempeh, soy chunks, edamame) | Complete protein, strong trial evidence | Favour minimally processed forms |
| Legumes (dal, rajma, chana, frijoles) | Protein plus fibre | Lower in methionine; pair with grains |
| Grains (wheat, rice, oats, maize) | Add protein at volume | Lower in lysine; pair with legumes |
The soy and testosterone myth
Many men avoid tofu because they have heard soy lowers testosterone. The worry comes from isoflavones, plant compounds that can weakly interact with estrogen receptors.
The clinical data do not support it. A 2021 meta-analysis in Reproductive Toxicology pooled 41 clinical studies in men and found no significant effect of soy protein or isoflavones on total or free testosterone, estradiol or estrone, regardless of dose or study length. Tofu, tempeh, soy milk and soy chunks are fair game. If you are worried about low testosterone, sleep, body fat, training and medical causes matter far more, and that is a conversation for your doctor.
Nutrients to watch
A lacto-ovo vegetarian diet covers most needs. A vegan diet needs more attention.
Vitamin B12
Natural B12 comes almost only from animal foods. Adults need 2.4 mcg a day. A cup of milk gives about 1.3 mcg and an egg about 0.5 mcg, so regular dairy and eggs get you close. Vegans need fortified foods or a supplement. Risk rises with age and with long-term metformin or acid-reducing drugs. See our vitamin B12 guide for vegetarians.
Iron
Men need 8 mg a day, but the NIH notes vegetarians need almost twice that because plant (non-heme) iron is absorbed less well. Eat lentils, chickpeas, beans, tofu, fortified cereals and greens with vitamin C, such as lemon on dal or tomato in rajma, and drink tea or coffee between meals. Men rarely need iron supplements, so only take one if a blood test shows you need it.
Zinc
Men need 11 mg a day. Phytates in beans and whole grains reduce absorption. Dairy, eggs, pumpkin seeds, cashews, chickpeas and tofu help, and soaking, sprouting and fermenting (idli, dosa, sourdough) lower phytates.
Omega-3 fats
Men need about 1.6 g a day of ALA, found in flaxseed, chia and walnuts. The body converts ALA to EPA and DHA, but the NIH reports conversion below 15%. If you eat no fish, algal oil supplies DHA and sometimes EPA. See our omega-3 guide for men over 35.
Vitamin D
Adults up to 70 need 600 IU (15 mcg) a day, with an upper limit of 4,000 IU. Few plant foods contain much, so sunlight, fortified milks and UV-exposed mushrooms are your main sources. Office workers are often low regardless of diet, so ask about a blood test.
Iodine
Adults need 150 mcg a day. Dairy, eggs and seafood are major sources, so vegans and people who skip iodised salt are at higher risk. Sea salt and Himalayan salt are usually not iodised.
| Nutrient | Daily target (men) | Vegetarian sources |
|---|---|---|
| Vitamin B12 | 2.4 mcg | Milk, yogurt, eggs, fortified foods |
| Iron | 8 mg (vegetarians need almost double) | Lentils, beans, tofu, greens, plus vitamin C |
| Zinc | 11 mg | Dairy, eggs, pumpkin seeds, cashews, tofu |
| Omega-3 (ALA) | 1.6 g | Flax, chia, walnuts; algal oil for DHA |
| Vitamin D | 600 IU (to age 70) | Sunlight, fortified milks, UV mushrooms |
| Iodine | 150 mcg | Iodised salt, milk, yogurt, eggs |
Safety note: Do not start iron, zinc, vitamin D or iodine supplements on guesswork; too much can be harmful. Get blood work first. If you take metformin, acid-reducing drugs, thyroid medication or blood thinners, check with your doctor before adding supplements or making big diet changes. If you have kidney disease, ask your doctor about safe protein targets before raising your intake.
A sample 140 g protein vegetarian day
A lacto-ovo vegetarian day for a man of around 80 kg who trains in the evening, with Indian-style and Latin American-style options. Protein figures are approximate and vary by brand, recipe and portion.
| Meal | Indian-style | Latin American-style | Protein |
|---|---|---|---|
| Breakfast | 2 moong dal chillas (60 g dry dal) with 60 g paneer, glass of milk | Huevos pericos (3 eggs), small arepa with 30 g queso fresco, glass of milk | ~33 g |
| Snack | 200 g Greek yogurt or hung curd, small handful of peanuts | 200 g Greek yogurt with fruit, small handful of peanuts or pumpkin seeds | ~25 g |
| Lunch | 1 cup cooked rajma or chana, 2 rotis, 2 boiled eggs or 100 g tofu, salad | 1 cup cooked frijoles, rice, 2 boiled eggs, hogao and avocado | ~30 g |
| Post-workout | 1 scoop whey or soy protein, banana | 1 scoop whey or soy protein, banana | ~25 g |
| Dinner | Tofu or soy-chunk curry (150 g tofu or 40 g dry chunks), bowl of dal, 1 to 2 rotis, vegetables | Lentil stew (1 cup cooked lentils) with 80 g queso campesino, vegetables, small portion of rice | ~30 g |
| Total | Five eating occasions | ~140 g | |
- Anchor every meal with protein: dairy, eggs, soy or a full bowl of legumes.
- Batch-cook legumes: one pressure cooker of rajma or frijoles covers several lunches.
- Keep a protein powder for gaps: whey if you eat dairy, soy or pea-rice if you do not.
- Add a tablespoon of flax or chia daily for ALA.
- Limit fried snacks, sweets and refined flour, which push you toward the unhealthy end of the scale.
FAQ
Can men over 35 build muscle on a vegetarian diet?
Yes. Trials show similar gains when total protein is matched and you train consistently. Aim for about 1.6 to 2.0 g/kg a day over several meals.
Do I need to combine proteins at every meal?
No. A variety of legumes, grains, dairy, soy, nuts and seeds over the day covers your amino acid needs.
Will tofu or soy milk lower my testosterone?
No. A meta-analysis of 41 clinical studies in men found no effect of soy or isoflavones on testosterone or estrogen.
Is a plant-based diet automatically good for my heart?
No. The benefits in cohort studies come from whole grains, legumes, nuts, fruit and vegetables. Refined grains, sweets, fries and sugary drinks are linked to higher risk, even with no meat.
Which blood tests should vegetarians ask about?
Ask your doctor whether B12, ferritin, vitamin D and a lipid panel make sense for you. Vegans may also discuss iodine and zinc.
Free tools: get a 7-day plant-based plan from the meal planner and build vegan high-protein meals with the protein plate builder.
Sources
- Satija A, et al. Healthful and unhealthful plant-based diets and coronary heart disease. JACC, 2017. ACC summary
- Satija A, et al. Plant-based dietary patterns and type 2 diabetes. PLOS Med, 2016. PMC
- Tong TYN, et al. Ischaemic heart disease and stroke in meat eaters, fish eaters and vegetarians (EPIC-Oxford). BMJ, 2019. BMJ
- Hevia-LarraÃn V, et al. High-protein plant-based vs protein-matched omnivorous diet for resistance training. Sports Med, 2021. DOI
- Messina M, et al. Soy vs animal protein and gains in muscle mass and strength. IJSNEM, 2018. PubMed
- Morton RW, et al. Protein supplementation and resistance training gains: meta-analysis. Br J Sports Med, 2018. BJSM
- van Vliet S, Burd NA, van Loon LJC. Anabolic response to plant- vs animal-based protein. J Nutr, 2015. ACU Research Bank
- Reed KE, et al. Neither soy nor isoflavone intake affects male reproductive hormones. Reprod Toxicol, 2021. PubMed
- Melina V, et al. Position of the Academy of Nutrition and Dietetics: Vegetarian Diets. 2016. PubMed
- NIH ODS: Vitamin B12
- NIH ODS: Iron
- NIH ODS: Zinc
- NIH ODS: Omega-3 fatty acids
- NIH ODS: Vitamin D
- NIH ODS: Iodine
This article is for general education and is not medical advice. Check with your doctor before starting a new training or nutrition plan, especially if you have a health condition.
