SlimFast Ready to use milkshakes can be used on the go as a meal replacement drink for weight control. Packed with everything you need and only 204 kcal per serving this Vanilla flavoured multipack contains 6 individual bottles. The ready to drink milkshakes are designed as a meal replacement drink for weight control to help keep the weight off as part of the Slim Fast 3. 2.1 Plan. Each portion contains 23 essential vitamins and minerals with 204 calories, 15g of protein per serving and 4. 9g of fibre. Key Features of Slim Fast Milkshake Multipacks Designed for use on the go High in protein High in fibre23 essential vitamins and minerals per portion