Heinz Tomato Soup is 74 kcal per 200ml serving — the lowest calorie mainstream tinned soup in UK supermarkets. Covent Garden Butternut Squash is 76 kcal per 200ml. Most tinned vegetable soups come in under 100 kcal per half-tin, making soup one of the most filling low-calorie lunches available.
The issue with shop-bought soup is sodium, not calories. Most tinned soups are low calorie but high in salt — around 1g per serving. For weight loss, that does not affect the calorie count, but it affects water retention which can show on the scales. Homemade soup solves both: lower sodium, lower calories, and you control exactly what goes in.
This guide covers calories and Slimming World syn values for every popular tinned and fresh soup in UK supermarkets, plus the lowest calorie homemade soup options.
Heinz Tomato Soup contains 74 kcal per 200ml serving — the lowest calorie mainstream tinned soup in the UK. Baxters Healthy Choice Tomato & Brown Lentil is 71 kcal per 200ml. Both are free on Slimming World for a half-tin serving as long as no cream or oil is added.
Homemade soups made with stock, vegetables, and no added fat or cream are even lower — a homemade tomato and vegetable soup can come in under 60 kcal per 300ml bowl and costs zero syns. For weight loss on a tight calorie budget, homemade soup is the single most efficient low-calorie filling meal available.
The table below covers calories and Slimming World syn values per 200ml serving for the most popular tinned and carton soups in UK supermarkets.
| Soup | Serving | Calories | SW Syns | WW Points |
|---|---|---|---|---|
| Heinz Tomato Soup | 200ml | 74 kcal | Free | 2 |
| Baxters Healthy Choice Tomato & Lentil | 200ml | 71 kcal | Free | 2 |
| Heinz Cream of Chicken | 200ml | 90 kcal | 1 | 3 |
| Heinz Lentil Soup | 200ml | 95 kcal | Free | 3 |
| Covent Garden Butternut Squash | 200ml | 76 kcal | Free | 2 |
| Covent Garden Tomato & Basil | 200ml | 82 kcal | Free | 2 |
| New Covent Garden Chicken | 200ml | 88 kcal | Free | 2 |
| Heinz Cream of Tomato (condensed) | 200ml made up | 100 kcal | 1 | 3 |
| Baxters Chunky Minestrone | 200ml | 65 kcal | Free | 2 |
| Covent Garden Pea & Ham | 200ml | 93 kcal | Free | 3 |
| Covent Garden Leek & Potato | 200ml | 96 kcal | Free | 3 |
| Covent Garden Stilton & Broccoli | 200ml | 140 kcal | 3 | 5 |
Syn values are based on ingredients — soups made with cream or cheese carry a syn cost even if the calorie count looks low per serving. Most plain vegetable and tomato soups are free on Slimming World regardless of brand.
Heinz Tomato Soup (the standard tinned variety) is free on Slimming World per half-tin serving. The ingredients are tomatoes, water, sugar, modified starch, and salt — no cream or fat that would trigger a syn cost. The condensed version made up with water is also free. Made up with milk adds syns depending on how much milk is used.
Heinz Cream of Tomato Soup is slightly different — the "cream" version contains a small amount of cream, which adds around 1 syn per 200ml serving. The standard tomato is free; the cream of tomato is not quite. Check the tin — the standard red and white tin is free; the creamier version has a different recipe.
A homemade vegetable soup made with stock, onions, carrots, celery, and tinned tomatoes contains approximately 50–70 kcal per 300ml bowl and is completely free on Slimming World. A homemade lentil soup (red lentils, onion, stock, cumin) comes in at around 120–150 kcal per bowl and is also free.
The lowest calorie homemade soups all follow the same formula: stock base, no added oil, no cream, vegetables or pulses as the bulk. Blended vegetable soups (carrot and coriander, tomato and basil) are typically 50–80 kcal per bowl. Chunky pulse soups (lentil, minestrone, split pea) are 100–150 kcal per bowl but considerably more filling.
A homemade leek and potato soup made without cream or butter — leeks, potatoes, stock, and seasoning — is free on Slimming World. Potatoes and leeks are both Free Foods on SW.
Shop-bought leek and potato soup varies. Covent Garden Leek & Potato is free at 96 kcal per 200ml because it uses a stock base rather than cream. Some supermarket own-brand versions add cream or butter, which adds syns. Always check the ingredients rather than assuming — a leek and potato soup without cream listed in the ingredients is free; one with cream is not.
Most Batchelors Cuppa Soups are 1–2.5 syns per sachet depending on flavour. They are not free, but they are low syn — a Tomato Cuppa Soup is around 1 syn and a Chicken Noodle is around 1.5 syns. The syn cost comes from maltodextrin and small amounts of fat in the powder.
Cuppa Soups are most useful as a between-meal snack rather than a meal replacement — the calorie content (50–80 kcal per sachet) is not enough to replace a proper lunch. As a mid-afternoon snack to bridge the gap before dinner, 1.5 syns for a Cuppa Soup is reasonable value. The full Cuppa Soups syn guide covers every flavour in detail.
Broth-based chunky soups — minestrone, lentil, vegetable — are the best soups for weight loss. Research from the Penn State University food lab found that eating a low-calorie soup before a meal reduced total meal calorie intake by 20% on average, because the bulk and liquid created satiety before the main course arrived.
The mechanism is straightforward: liquid volume in the stomach triggers stretch receptors that signal fullness. A 300ml bowl of vegetable soup before a meal creates the same fullness signal as eating a much larger portion of food. For members on Slimming World, having a bowl of free homemade soup as a starter before the main meal is one of the most effective ways to reduce evening calorie intake without restricting anything.
For more high-protein Free Foods to build meals around, see calories in chicken UK and calories in eggs UK.
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