Lowest Calorie Soup UK: Tinned, Carton and Homemade Compared (2026)

Fancy a comforting bowl of soup that won't break your calorie budget? You might be surprised that a classic like Heinz Tomato Soup is actually the lowest-calorie mainstream tinned soup in UK supermarkets, at just 74 kcal per 200ml! Perfect for a quick, warming lunch.

Now, while shop-bought soups are brilliant for convenience, do keep an eye on the sodium content. Most tins are low-calorie but can be pretty high in salt – we’re talking around 1g per serving! For weight loss, it won’t affect your calorie count directly, but it can make you retain water, which might show up on the scales. If you’re like me and hate seeing that number jump, homemade soup is a winner – lower in sodium, fewer calories, and you know exactly what's gone into it.

Right, let’s get stuck in! This guide is packed with all the calorie counts and Slimming World syn values for nearly every popular tinned and fresh soup you’ll find in UK supermarkets, plus my top picks for the lowest calorie homemade soup options.

What's the absolute lowest calorie soup in the UK?

So, what's the actual lowest calorie soup you can pick up? It’s often a tie between a couple of fantastic options. Your classic Heinz Tomato Soup comes in at just 74 kcal per 200ml serving – honestly, it's a staple in my cupboard for a reason! But a real hidden gem is Baxters Healthy Choice Tomato & Brown Lentil, which nudges ahead at 71 kcal per 200ml. Both are cracking choices and totally Free on Slimming World for a half-tin serving, provided you don't add any extra cream or oil, of course.

Now, if you really want to keep things super low-cal, homemade is the way to go. Soups whipped up with just stock, plenty of veggies, and no added fats or cream are even leaner. I often make a big batch of tomato and vegetable soup, and it easily comes in under 60 kcal per generous 300ml bowl and is completely zero syns. Seriously, if you're watching your calories, homemade soup is one of the most efficient, filling, and budget-friendly meals out there.

Which Soups Are the Lowest in Calories? (Full UK Comparison)

Right, let’s get down to brass tacks! The table below is your go-to guide, covering all the calories and Slimming World syn values per 200ml serving for the most popular tinned and carton soups you'll spot in UK supermarkets. I found this super handy when I was first getting to grips with syns!

Just a little heads-up on those syn values: they’re all based on the ingredients. So, if a soup has cream or cheese in it, it'll carry a syn cost, even if the calorie count seems pretty low for a serving. Generally, though, most plain vegetable and tomato soups are Free on Slimming World, no matter which brand you pick up.

Is That Classic Heinz Tomato Soup Free on Slimming World?

Good news! Your standard tinned Heinz Tomato Soup is indeed Free on Slimming World for a half-tin serving. I know, it's a lifesaver for a quick lunch! The ingredients are exactly what you'd expect: tomatoes, water, sugar, modified starch, and salt – crucially, no cream or fat to rack up those syns. Even the condensed version, when you make it up with water, is free. Just remember, if you fancy adding milk, that's where the syns will start to creep in, depending on how much you use.

Now, here’s a common little mix-up: Heinz Cream of Tomato Soup is a bit different. As the name suggests, the "cream" version does have a small amount of actual cream in it, which adds around 1 syn per 200ml serving. So, the bog-standard red and white tin is your Free Food friend, but the creamier version isn't quite. Always double-check the tin to be sure!

What's the Absolute Lowest Calorie Homemade Soup You Can Make?

Okay, if you’re pulling out the big guns for low calories and zero syns, homemade is your champion. A simple homemade vegetable soup – think stock, onions, carrots, celery, and a tin of tomatoes – will clock in at a tiny 50–70 kcal per generous 300ml bowl and is completely Free on Slimming World. Or, if you fancy something a bit more substantial, a homemade lentil soup (red lentils, onion, stock, a hint of cumin) is around 120–150 kcal per bowl and also completely Free. I often batch cook these for lunches throughout the week!

The secret to the lowest calorie homemade soups is actually really straightforward: stick to a stock base, absolutely no added oil or cream, and pile in the vegetables or pulses for the bulk. Blended veggie soups, like my favourite carrot and coriander or a fresh tomato and basil, are usually only 50–80 kcal a bowl. If you want something chunkier and more satisfying, pulse soups like lentil, minestrone, or split pea will be 100–150 kcal per bowl, but they’ll keep you fuller for ages.

How Many Syns Are in Leek and Potato Soup?

Right, let's talk about a proper British classic: Leek and Potato soup! If you make it yourself without any cream or butter – just leeks, potatoes, stock, and your favourite seasonings – it’s absolutely Free on Slimming World. Both potatoes and leeks are brilliant Free Foods, which is why I love this one for a hearty meal.

When it comes to shop-bought leek and potato soup, things can get a bit varied. For example, the Covent Garden Leek & Potato is free at 96 kcal per 200ml, because they use a stock base, not cream. But be warned, some supermarket's own-brand versions do sneak in cream or butter, and that'll definitely add syns. So, my top tip is always, always check the ingredients list rather than just assuming. If 'cream' isn't in there, you're usually good to go!

Are Batchelors Cuppa Soups Free on Slimming World?

Ah, the trusty Cuppa Soup! Perfect for a desk lunch or a quick pick-me-up. Most Batchelors Cuppa Soups will cost you between 1 and 2.5 syns per sachet, depending on the flavour. So, no, they're not Free, but they are pretty low syn – a Tomato Cuppa Soup, for example, is around 1 syn, and a Chicken Noodle is about 1.5 syns. The syns come from things like maltodextrin and those tiny bits of fat hiding in the powder, which honestly surprised me when I first looked it up!

I tend to see Cuppa Soups more as a handy between-meal snack rather than a full meal replacement, if I'm honest. With only 50–80 kcal per sachet, they're just not quite enough to properly fill you up for lunch. But for that dreaded mid-afternoon slump, when you need something warm to bridge the gap before dinner, 1.5 syns for a Cuppa Soup is a perfectly reasonable value, in my opinion. If you want to dive deeper, I've got a full Cuppa Soups syn guide that covers every single flavour in detail.

Which Soups Are Actually Best for Weight Loss?

So, if you’re aiming for weight loss, which soups should you be reaching for? My go-to recommendation is always broth-based chunky soups – think minestrone, lentil, or a hearty vegetable soup. There's actually some science behind it! Research from the Penn State University food lab found that having a low-calorie soup before your main meal can reduce your total calorie intake by a whopping 20% on average. How brilliant is that? It’s all down to the bulk and liquid making you feel fuller before you even get to the main course.

The way it works is actually pretty clever: when your stomach fills with liquid, it triggers these 'stretch receptors' that send signals to your brain telling it you’re full. So, a generous 300ml bowl of vegetable soup before dinner essentially gives you that same 'I’m satisfied' signal as eating a much larger plate of food. For us Slimming World members, having a big bowl of Free homemade soup as a starter before your evening meal is genuinely one of the most effective ways to cut down on those evening calories without feeling like you're missing out on anything at all.

For more high-protein Free Foods to build meals around, see calories in chicken UK and calories in eggs UK.