Protein shakes: how to choose and how much to take
Protein shakes are protein powder mixed with water or milk. They are convenient when it is difficult to get enough protein from food.
In this article you will learn how the types of protein differ, how much protein you actually need and what to look for on the label.
In brief. An adult needs about 0.83 g of protein per kilogram of body weight per day, and people who exercise actively need more.1,2 20–40 g of protein is enough for one shake.2 Whey protein suits most people, isolate contains less lactose, and plant proteins suit vegans. A shake is not a substitute for a varied diet.
Who needs protein shakes?
Protein contributes to a growth in and the maintenance of muscle mass.3 Most people get enough from their usual food.1 A shake can be useful when you:
- exercise a lot and need more protein;
- eat little meat, fish or dairy products;
- do not have time for a proper meal.
Example. For a person weighing 70 kg, the general requirement is about 58 g of protein per day.1 If they exercise actively, 1.4–2.0 g/kg is recommended, i.e. about 98–140 g.2 The difference is easier to reach with one shake a day.
Which types of protein should you choose?
| Type | What is worth knowing | What it means for you |
|---|---|---|
| Whey concentrate | Milk protein, the most popular and often the cheapest type. | Suitable for most people, but contains some lactose. |
| Whey isolate | More refined milk protein, with less fat and lactose. | Convenient if you are sensitive to lactose. |
| Casein | Slowly digested milk protein.2 | Often chosen in the evening. |
| Plant-based (pea, soy, rice) | Usually contain less leucine, an amino acid that is important for muscles.2 | Suitable for vegans. Choose a blend of several plant sources or a slightly larger serving. |
How many protein shakes a day?
20–40 g of protein per serving is recommended, and it is worth spreading protein intake throughout the day, every 3–4 hours.2 For most people 1 shake a day is enough, with the remaining protein coming from food.
Example. If you eat 80 g of protein a day and you need 110 g, one shake with roughly 25–30 g of protein is enough.
How to read the label of a protein powder
- Protein content per serving, not per 100 g. Compare how many grams of protein you get from one scoop.
- Sugar and salt. Some plant-based products contain more salt than you might expect.
- The “high protein” claim may only be used when protein provides at least 20% of the energy value of the product.4
- Allergens: milk, soy, gluten.
- Certificates (“Informed Sport”, “Kölner Liste”), if you take part in competitions with doping control.
Are protein shakes suitable for people who are lactose intolerant?
Many people with lactose intolerance can consume up to 12 g of lactose at one time without symptoms.5 Whey isolate usually contains little lactose, and plant proteins contain none. If you get symptoms even from a small amount, choose products labelled “lactose-free” or plant proteins.
Who should be careful?
- People with kidney disease – discuss your protein intake with your doctor.
- People allergic to milk or soy – read the ingredients carefully.
- Under 18s – most protein powders are intended for adults; for teenagers, food is recommended first.
We write more about other sports supplements in the article “Supplements for athletes”.
Selected protein products
Commercial information. The products listed here are available in our shop. This is not an effectiveness ranking. Before buying, check the ingredients and directions for use on the product page.
100% Whey Protein, Vanilla - 400g - Nutrend
A blend of whey concentrate and isolate, 22 g of protein in a 30 g serving. The small pack (13 servings) is suitable for trying out the flavour.6
Clear Isolate, Red Fruits - 500g - Weider
Clear whey isolate, 21 g of protein in a 25 g serving. The manufacturer states that the product is lactose-free and sugar-free. Mix with cold water, not milk.7
Pea Protein, Unflavored - 907g - NOW Foods
Unflavoured pea protein, 24 g of protein and about 2 g of leucine per serving. Suitable for mixing into porridge or a fruit shake.8
Vegan Protein, Vanilla - 540g - Weider
A blend of pea and rice protein, 23 g of protein in a 30 g serving. A serving contains 1.2 g of salt, so include it in your daily intake.9
Frequently asked questions
Are protein shakes suitable for women?
Yes. Protein requirements are calculated according to body weight and activity level, not sex.1 A protein shake on its own does not “build” muscle – training is needed for that.
Can a shake replace a meal?
Occasionally, when you do not have time, yes. However, an ordinary shake does not contain as much fibre, vitamins and minerals as a complete meal, so it should not replace one regularly.
Mix with water or milk?
With milk, a shake is more filling and contains more protein and calories. With water, it is lighter. Mix clear isolates only with water.
Scientific sources
- EFSA NDA Panel. Scientific Opinion on Dietary Reference Values for protein. EFSA Journal. 2012;10(2):2557. doi:10.2903/j.efsa.2012.2557
- Jäger R, Kerksick CM, Campbell BI et al. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20. doi:10.1186/s12970-017-0177-8
- Commission Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods (consolidated version). EUR-Lex
- Regulation (EC) No 1924/2006 on nutrition and health claims made on foods, Annex. EUR-Lex
- EFSA NDA Panel. Scientific Opinion on lactose thresholds in lactose intolerance and galactosaemia. EFSA Journal. 2010;8(9):1777. doi:10.2903/j.efsa.2010.1777
- Nutrend. 100% Whey Protein, Vanilla, 400 g. Product label.
- Weider. Clear Isolate, Red Fruits, 500 g. Product label.
- NOW Foods. Pea Protein, Unflavored, 907 g. Product label.
- Weider. Vegan Protein, Vanilla, 540 g. Product label.
Disclaimer. This article is for informational purposes only and does not replace a consultation with a doctor or pharmacist. Protein powders and food supplements are not intended to treat or prevent diseases and do not replace a varied diet and a healthy lifestyle. If you have a chronic illness or take medicines, consult a healthcare professional before changing your diet.
