Powders, shakes and convenience
Meal replacement shake on a GLP-1: protein, portions and how to actually eat it
About 6 g of protein per 100 g (3.5 oz), made up as directed, per 100 ml, for around 70 calories. One made-up shake, about 350 g (12.3 oz), gives roughly 21 g of protein for 245 calories.
To reach 30 g of protein from meal replacement shake alone you would need about 500 g (17.6 oz). On a small appetite that is often more than one sitting allows, which is why we pair it rather than chase the whole target from one food.
How meal replacement shake sits on a GLP-1
Meal replacement shakes, Optifast, Huel, SlimFast and the like, are built to stand in for a meal: about 20 to 30 g of protein per serve with vitamins, minerals, some fat and carbohydrate, for 200 to 400 calories. Made up, that is roughly 6 g of protein per 100 ml (3.4 fl oz). On a GLP-1 they are the meal for the day when a meal is not going to happen, and the risk is the opposite one: sliding into two or three shakes a day, which is a very low calorie diet, and that is something to do with your prescriber, not on your own.
When your appetite is small
Use one shake a day, at the meal you most often skip, and make it up on milk instead of water if the label allows, which lifts a 20 g serve to about 28 g. Sip it over half an hour rather than drinking it in one go. Compare the protein per serve between brands before you buy, because it ranges from about 15 g to 30 g and the lower end will not hold your muscle.
Three ways to prepare it
One serve on milk at the meal you skip
Made on 300 ml (10 fl oz) of milk in a shaker. About 28 g, and it is the whole meal, so nothing else has to be decided.
Made thin and sipped from a bottle through the morning
Extra liquid, a bottle with a lid, and it goes down slowly with no pressure to finish.
Blended with ice and a banana into a thick shake
For the days when you want it to feel like food. Blended with ice it eats with a spoon.
What to eat it with
Milk to make it up, a banana or a few berries blended in. Nothing else; the shake is designed to be complete on its own.
How it compares
| Food | Protein per 100 g | Energy per 100 g | |
|---|---|---|---|
| Meal replacement shake | about 6 g | 70 kcal | this page |
| Ready-to-drink shake | about 8 g | 55 kcal | See the page |
| Whey concentrate | about 78 g | 400 kcal | See the page |
| Milk | about 3.5 g | 64 kcal | See the page |
All figures are typical values for the food as eaten, made up as directed, per 100 ml, not laboratory figures for a particular brand.
Australian, US and UK names
Optifast and Optislim in Australia and the UK, SlimFast in all three, Huel in the UK and the US, Soylent in the US. Protein per serve ranges from about 15 g in the cheaper diet shakes to 30 g in the newer complete food brands, so the figures here are representative and the label is the number that matters.
Questions people ask
Can I live on meal replacement shakes while on a GLP-1?
One shake a day as the meal you cannot face is a sensible tool. Replacing most meals is a very low calorie diet, which drops muscle fast unless it is planned and supervised, and that is a decision for your prescriber. Whatever you do, keep the protein at 20 g or more per shake.
Your number comes first
Knowing what is in a food only helps once you know how much you are aiming for. The target is 1.2 to 1.6 g of protein per kg of your goal weight, not your current weight, which for most people is 90 to 140 g a day.
Work out your protein targetMore on eating well when your appetite is small: high protein foods for a small appetite, how much protein on a GLP-1, and every food we have written up. The whole system in five documents is the Keep Muscle Kit, A$47 / US$29 / £23.
EverStrong provides nutrition and strength coaching and education. It is not medical advice and does not replace your prescribing doctor.