You want to get stronger, but you would rather use a plant-based protein—or simply enjoy tofu more than another chicken dinner. Does that mean accepting worse results? Soy is one of the better-studied plant proteins, and the research gives you a practical option rather than a reason to worry about choosing the “wrong team.”
Soy protein can fit a strength-training diet. Research comparing soy and milk proteins generally does not show a clear difference in longer-term muscle gains. That is useful reassurance, with an important detail: the amounts and types of protein used in the studies still matter. [1]
What the wider evidence says
A 2025 review included 43 randomised trials comparing plant and animal protein. In the 17 trials contributing to the soy-versus-milk muscle-mass comparison, the pooled difference was close to zero. The broader comparison across all plant proteins modestly favoured animal protein, so it would be inaccurate to turn the soy finding into a claim that every plant product has identical evidence. [1]
The trials varied in participant age, training, protein dose and duration. Many had some risk-of-bias concerns. The review therefore supports soy as a reasonable choice; it does not prove that every serving, product or dietary pattern produces exactly the same result in every person. [1]
One trial shows why the serving matters
A 12-week trial enrolled 61 young adults new to strength training; 48 completed it. Participants trained under supervision three times weekly and received either 19 grams of whey protein or 26 grams of soy protein, chosen to provide the same amount of leucine. Both groups improved lean mass and strength, without a significant difference between groups. [2]
Notice that the protein amounts were not equal. The study matched leucine, an amino acid, rather than matching the weight of the supplement. It also had no training-only control group, so it cannot tell us how much of the improvement required a powder. The participants were young and previously untrained; results need not transfer unchanged to experienced athletes or older adults. [2]
You do not need to reproduce that protocol at dinner. Its practical lesson is to compare what a serving provides instead of assuming that two scoops—or two drinks—are nutritionally interchangeable.
Choose the food or product for the job it needs to do
A meal ingredient, a convenient drink and a concentrated powder solve different problems. The following examples are ways to organise meals, not the interventions used in the trials:
| Situation | An option to try | What to check |
|---|---|---|
| You need an ordinary dinner | Tofu or tempeh with rice, vegetables and a sauce you enjoy | Portion size, protein on the label and whether the meal is enough for you |
| You want an easy breakfast | Oats made with a fortified soya drink, with fruit and nuts | Protein and fortification vary between products |
| You need something portable | A suitable soy-based snack or drink alongside your usual food | Whether it actually fills the gap you identified |
| You struggle to reach your planned protein intake through meals | A soy protein powder can be a convenient addition | Protein per serving, ingredients, taste, tolerance and cost |
For a fully vegan diet, overall adequacy includes more than protein. NHS guidance highlights fortified foods and attention to nutrients such as B12, calcium, iodine and vitamin D. A protein powder does not automatically cover those needs. Check the label of your actual product. [3]
Compare cost without being distracted by tub size
Here is an invented shopping example. A £20 tub contains 20 servings, with 25 grams of protein in each. That is £1 per serving. A £15 tub contains 15 servings with 15 grams of protein each. It also costs £1 per serving, but provides less protein.
To compare the same protein amount, the second product would cost about £1.67 per 25 grams of protein: £1 multiplied by 25/15. These are hypothetical prices, not recommendations for a brand. The comparison is useful when the specific job is adding protein; it does not measure the overall value of a complete food or meal.
Also consider waste. A large discounted tub is poor value if you dislike the flavour and stop using it. When possible, begin with a small pack of a product you tolerate rather than committing to months of servings.
Make one meal work before redesigning the whole week
If tofu has disappointed you before, change one preparation detail. Try a firmer product for a crisp-edged stir-fry, cut it into smaller pieces so more surface meets the pan, or use a sauce with flavours you already like. Follow the product's preparation and storage instructions. This is cooking advice, not a claim that a particular method improves muscle growth.
Choose one repeatable meal and keep the rest of the day familiar. For example, add a tofu rice bowl to your weekly rotation while continuing your usual breakfast and lunch. Once you know you enjoy it and can prepare it easily, decide whether another swap would help.
If soy does not suit your preferences—or you have a soy allergy—choose another protein source. This article is not a reason to force a food you cannot safely eat or do not enjoy. A workable diet allows alternatives.
Put the protein choice beside the training plan
The comparative trials took place within specific programmes and diets. Buying a particular powder is not the same as following those programmes. Keep the practical questions together: what training will you repeat, what meals can you manage, and what gap would a supplement fill?
For the wider food-planning question, read Enough protein, without planning your life around it. For a training starting point, use your first two strength sessions.
If you want help connecting meals and training into a routine, explore WeightStart. The useful purchase is support that addresses a real obstacle in your week—not reassurance that one protein label makes you a more serious exerciser.
Sources and reading notes
Updated 2 October 2026. Meal ideas and cost calculations are editorial examples. The review includes individual trials, so it should not be counted as entirely independent evidence from the trial below.
- Reid-McCann RJ, Brennan SF, Ward NA, et al. Effect of Plant Versus Animal Protein on Muscle Mass, Strength, Physical Performance, and Sarcopenia: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Nutrition Reviews. 2025;83:e1581–e1603. doi:10.1093/nutrit/nuae200. Full-text subgroup findings and limitations assessed.
- Lynch HM, Buman MP, Dickinson JM, et al. No Significant Differences in Muscle Growth and Strength Development When Consuming Soy and Whey Protein Supplements Matched for Leucine Following a 12 Week Resistance Training Program in Men and Women: A Randomized Trial. International Journal of Environmental Research and Public Health. 2020;17:3871. doi:10.3390/ijerph17113871. Full-text methods and limitations assessed; student/university research grants, no conflicts declared.
- NHS. The vegan diet. Reviewed 5 June 2026.