Looking for the best diet shakes to support your weight loss goals? Here's a quick guide to some of the top options in the UK, including key features, nutritional breakdowns, and pricing. Diet shakes can offer a convenient way to manage calorie intake by replacing a meal with a mix of protein, fibre, and essential nutrients — helping support a calorie deficit.

Top picks:

• Ensure COMPLETE: 350 calories, 30g protein, 4g fibre. Includes plant-based omega-3 for added health benefits.
• SlimFast: 180 calories, 22% protein, 54% carbs. Affordable with a wide variety of flavours.
• SCI-MX nutrition: 200 calories, 25g protein, green tea extract for metabolism support.‍
• Atkins plus: 190 calories, 30g protein, 7g fibre. Low in sugar and carbs, perfect for low-carb diets.

However, relying too heavily on shakes may not suit everyone. Some options lack whole food ingredients, can be overly processed, and may not teach long-term habits around hunger, portion sizes, or how different foods affect your body.

If you're after a more sustainable and personalised approach, alternatives like Vively’s CGM-guided program can help you better understand how your body responds to food in real time — empowering you to make informed, lasting changes through real food rather than temporary fixes.

Quick comparison:

Key takeaways:

• High protein shakes (20–30g): Help with hunger control and muscle maintenance.
• Low sugar (<5g): Prevents blood sugar spikes.
• Fibre content (3–7g): Promotes fullness and supports digestion.
• Affordable options: SlimFast and SCI-MX Nutrition are budget-friendly without sacrificing quality.

To maximise results, replace 1-2 meals per day with a shake and pair it with a balanced diet and exercise. Always consult a healthcare professional before starting a new diet plan.

Curious about how protein affects your blood sugar? Read our guide on what protein does to glucose levels to understand its impact and how it can support better blood sugar control.

1. Ensure COMPLETE

Ensure COMPLETE is a meal replacement shake designed to provide balanced nutrition and support weight management. Each 8 fl oz serving packs 30 grams of protein and 350 calories for a filling and nutritious option.

Here’s a quick breakdown of its nutritional highlights:

The shake’s formula includes the Comfort Fibre Blend, which combines prebiotic fibre with key nutrients like zinc, vitamin A, and vitamins C and E. This blend supports digestion, boosts immunity, helps maintain muscle, and promotes a feeling of fullness.

It comes in three classic flavours—chocolate, vanilla, and strawberry - featuring a smooth and creamy texture. Plus, it’s gluten-free, suitable for those with lactose intolerance, and certified Halal and Kosher.

If you're interested in low GI options beyond diet shakes, check out our guide to the best low GI bread in the UK. It covers dietitian-approved picks that can help you manage blood sugar levels effectively.

2. SlimFast diet shake

SlimFast has been a go-to weight management option for over 40 years, offering a simple and balanced way to control calories while still getting key nutrients. Their shakes are designed to help maintain energy levels and support muscle health during weight loss.

A single 11 fl oz serving of the SlimFast Creamy Milk Chocolate Shake contains 180 calories. Its macronutrient breakdown is as follows: 54% carbohydrates, 22% protein, and 24% fat. SlimFast also stands out with its variety of flavours, catering to different taste preferences.

Here’s a quick look at its nutritional profile:

Flavour options include classics like Creamy Milk Chocolate, Strawberry Milk Shake, and Banana Milk Shake. For those looking for something different, the Advanced Nutrition line offers choices like French Vanilla, Cappuccino Delight, and Caramel Latte.

With its thoughtful formulation, SlimFast helps balance energy levels and preserve muscle, making it a practical pick for anyone focused on managing their weight effectively.

3. SCI-MX Nutrition diet shake

The SCI-MX Nutrition Diet Shake is designed to help with weight management while providing balanced nutrition. Each serving contains 200 calories, 25 grams of protein, and over 30% of your daily vitamins and minerals.

Here’s what makes it stand out:

• Green tea extract to help support metabolism
• CLA (Conjugated Linoleic Acid), known for aiding fat loss
• VIT-MIX trim blend for overall nutritional balance

Nutritional breakdown

With a price of £16.77 ($21.25) for a 1 kg container, each serving costs less than £1 ($1.27) [5]. This makes it an affordable option for a meal replacement.

For best results, replace one or two meals a day with this shake. Adding a serving of fruits or vegetables can provide extra fibre and nutrients.

4. Atkins Plus diet shake

Atkins Plus Diet Shake is designed to help with weight management by balancing protein and calories to curb hunger. Each 11-ounce serving packs 190 calories, 30 grams of protein, 7 grams of fibre, 8 grams of carbohydrates, 1 gram of sugar, and 5 grams of fat. Plus, it includes 20 vitamins and minerals to provide well-rounded nutrition.

Nutritional breakdown

Effectiveness for weight loss

Studies show that replacing a large portion of daily calories with meal replacement shakes can effectively support weight loss. In one analysis, participants who got about 60% of their daily calories from these shakes saw measurable results.

Looking for low-sugar drink options to complement your diet shakes? Check out our list of the 10 best low blood sugar drinks to keep your glucose levels steady and support your weight loss goals.

Key features

Atkins Plus Diet Shake stands out with the following:

• Low sugar: Just 1 gram of sugar and no added sweeteners.
• Complete nutrition: Packed with 20 essential vitamins and minerals.
• Convenient: Ready-to-drink, making it easy to fit into your day.
• Improved formula: Offers 50% more protein and 40% more fibre compared to Slim Fast High Protein Shakes, enhancing hunger control.

Best Overall Diet Shake

Atkins Plus Diet Shake takes the top spot for its impressive balance of low calories, high protein, and fibre—all key elements for effective weight loss. With 30g of protein and 7g of fibre, it supports muscle maintenance and satiety while keeping sugar and carbs low. It's also rich in vitamins and minerals, offering a convenient, ready-to-drink solution that suits a low-carb lifestyle.

While other options like Ensure COMPLETE offer more calories for those needing a full meal replacement, Atkins Plus hits the sweet spot for weight loss support, especially when paired with a healthy, whole-food diet.

Final thoughts: using diet shakes alongside CGMs

Diet shakes are a convenient way to support weight loss—especially when life gets busy or you’re aiming to manage calories without compromising on nutrition. But to really personalise your health journey, pairing these shakes with a Continuous Glucose Monitor (CGM) can give you powerful insights into how your body responds.

CGMs track your glucose levels in real time, helping you understand:

• Which shakes keep your blood sugar stable
• How different ingredients affect your energy and cravings
• When to adjust carbs, timing, or portion sizes for better results

As Charlotte Battle, Vively’s lead dietitian, explains:

“Understanding your personal glucose response can be a game-changer for weight loss. It helps you make smarter choices—whether it’s choosing the right shake or planning meals that truly work for your body.”

In short, the best diet shake is the one that fits your lifestyle, supports your goals, and keeps you feeling your best. Combine that with tools like a CGM, and you’ve got a much clearer path to sustainable results.