Weight Loss Fact Checker

Premier Protein vs Fairlife Core Power: which shake should you buy?

Two of America's best-selling protein shakes compared on protein, calories, sugar and what's in them, and why neither is a meal replacement.

By Carol Standing · Published 7 November 2026 · 2 min read

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Premier Protein and Fairlife Core Power sit near the top of Amazon's US protein shake best-sellers. Both are ready to drink and high in protein, but they're made differently and suit different people.

Side by side

Per bottlePremier ProteinCore Power 26gCore Power Elite 42g
Size11 to 11.5 fl oz14 fl oz14 fl oz
Protein30 g26 g42 g
Caloriesabout 160about 170about 230
Sugarabout 1 gabout 5 gabout 7 to 8 g
Main proteinMilk protein concentrate, calcium caseinateUltra-filtered milkUltra-filtered milk

Figures are from US labels and vary slightly by flavour. Check the bottle.

What's actually different

Premier Protein is built from milk proteins added to water, sweetened with sucralose and acesulfame K. That's why it can be so low in sugar and calories.

Core Power starts with milk that's filtered to concentrate the protein and reduce the sugar. It's closer to a flavoured milk. The sugar is mostly what's left of the milk's natural sugar.

For weight loss, Premier Protein gives the most protein for the fewest calories. Core Power Elite suits people who need a lot of protein, for example after a strength workout, and can afford the extra calories.

They're not meal replacements

Both are protein shakes, not meal replacements. In the UK, a food can only claim to help weight loss as a meal replacement if it provides 200 to 250 calories per meal with set levels of protein, vitamins and minerals. Premier Protein, at around 160 calories, is a snack.

The approved health claim for protein is simpler: protein contributes to the maintenance of muscle mass. That's useful when you're losing weight, because some of the weight lost can be muscle.

Our picks

1

Best for: The most protein for the fewest calories

Premier Protein 30g protein shake

30 g protein for about 160 calories and around 1 g sugar per bottle. Sweetened with sucralose and acesulfame K.

Worth knowing: The Café Latte flavour contains added caffeine.

See options on Amazon.com (affiliate link, opens in new tab)
2

Best for: People who prefer a milk-based shake

Fairlife Core Power 26g protein shake

Made from ultra-filtered milk. A 14 fl oz bottle has 26 g protein and around 5 g sugar.

See options on Amazon.com (affiliate link, opens in new tab)
3

Best for: Very high protein needs, such as after strength training

Fairlife Core Power Elite 42g

42 g protein per 14 fl oz bottle, for about 230 calories.

Worth knowing: More calories and sugar than the 26g version, so it's a bigger snack.

See options on Amazon.com (affiliate link, opens in new tab)

The short version

  1. Fewest calories per gram of protein: Premier Protein.
  2. Most protein per bottle: Core Power Elite.
  3. Neither is a meal replacement. Use them as a high-protein snack or with food.

Common questions

Can I use Premier Protein or Core Power as a meal replacement?

Not on their own. In the UK, a meal replacement for weight control has to provide 200 to 250 calories per meal with set amounts of protein, vitamins and minerals. Both are protein shakes, not meal replacements, so treat them as a high-protein snack or have them with food.

Do protein shakes help you lose weight?

A protein shake doesn't cause weight loss on its own. What matters is your overall calorie intake. The approved claim for protein is that it contributes to the maintenance of muscle mass, which matters when you're losing weight.

Can I buy them in the UK?

Both are American brands. You may find them on Amazon UK from importers, often at a higher price. UK alternatives are covered in our meal replacement comparison.

Sources we checked

  1. Premier Protein Vanilla 30g protein shake: nutrition and ingredients (H-E-B (retailer label listing))
  2. Core Power Elite 42g high protein shake: nutrition facts (Food Lion (retailer label listing))
  3. fairlife Core Power (Coca-Cola Canada)
  4. Commission Regulation (EU) 2016/1413: meal replacement health claims (UK version) (legislation.gov.uk)
  5. Great Britain nutrition and health claims (NHC) register (UK Government)

This article is general information, not medical advice. Speak to a doctor, pharmacist or other qualified clinician about your own health, especially before starting a supplement or if symptoms are new, severe or worrying.

Got a question about this, or a claim you want checked? Ask us.

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