Piled high with bacon, dunked into soup or sandwiched around classic cheese and pickle, few foods are woven into British life quite like bread.

We get through 11million loaves, or two to three slices each every day, with the factory-made, supermarket variety still the most popular.

But if you’re struggling to find a reason for your expanding waistline, your daily bread could be the culprit.

Many modern loaves bear little resemblance to traditional bread made from flour, water, yeast and salt. Instead, they’re often packed with ultra-processed ingredients – emulsifiers, preservatives and sugars – to keep them softer, fresher and harder to resist.

Scientists increasingly believe these additives alter how the body burns energy, setting us up for weight gain – even if we’re not eating more.

All of which means some bread is significantly healthier than others.

So which deserves a place in your trolley – and which could be causing you to pile on the pounds?

With nutritionist Laura Southern, founder of London Food Therapy, we analysed eight supermarket loaves and ranked them from best to worst...

Best for slimmers – if you can stomach the price

Waitrose Duchy Organic Seeded Sourdough, £2.50

Demand for sourdough is booming among middle-class shoppers looking for a loaf that’s a cut above ordinary sliced white. Almost half of Brits now say they buy the chewy fermented bread on a regular basis.

This Duchy Organic version is pricey but packs a nutritional punch – and is unlikely to add inches to your waistline.

Made with a ten-year-old starter for an authentic tang, it is slowly fermented, which can slow the digestion of carbohydrates so it won’t send blood sugar soaring like standard white bread – a process which can damage our metabolic response and lead to weight gain.

‘It contains sunflower, linseed and pumpkin seeds to boost the fibre and protein content, as well as offering good fats,’ says Laura. ‘It will keep you fuller for longer.’

Healthy, but not joyless.

Health rating: 10/10

Taste rating: 9/10

Rye to help you cut back on calories

M&S Wholegrain Sliced Rye, £2

With only four ingredients – wholegrain ground rye, water, salt and yeast – this dense, Scandinavian-style loaf is not an ultra-processed food (UPF). ‘Its ingredients are hard to fault,’ says Laura. ‘It’s exactly the type of bread I encourage my clients to eat.’

Wholegrain rye is very high in fibre – this loaf contains 10.2g per 100g, far more than most supermarket loaves. ‘Fibre slows digestion and helps stabilise blood sugar,’ she says.

Rye bread has a low glycaemic index, releasing glucose more slowly, rather than causing sharp blood sugar spikes. Studies have found rye can increase satiety hormones and reduce calorie intake later in the day. ‘However, it is high in salt, with 1.2g per 100g,’ says Laura. An acquired taste.

Health rating: 9/10

Taste rating: 7/10

Packed with grains – with a weight catch

Sainsbury’s Taste The Difference Soft Multiseed Farmhouse Wholemeal, £1.60

This loaf has a lot to recommend it. ‘The base is wholemeal flour, which keeps the whole grain intact, whereas white flour is refined and strips out the bran and germ,’ says Laura.

‘Wholemeal contains much more fibre, as well as B vitamins, iron and magnesium, which are largely lost in the refining process. It’s also packed with seeds.’

Soft, nutty and substantial, it makes a delicious sandwich. The catch? It also contains added wheat gluten, sugar, rapeseed and palm oils, soya flour and ascorbic acid – ingredients used to improve softness, shelf life and texture. ‘The sugar, added gluten and refined flour produce a higher glycaemic response than wholegrain flour alone, which can influence appetite regulation,’ says Laura. ‘The palm oil is not only high in saturated fat but also has environmental impacts.’

Health Rating: 8/10

Taste Rating: 8/10

Filling fibre to keep hunger at bay

Exceptional by Asda Wholemeal Superseeded Sliced Loaf, £1.47

‘Nutritionally, this is a pretty good choice, with a hefty 15 per cent seed content, including linseeds, pumpkin and sunflower seeds, boosting fibre, protein and healthy fats,’ says Laura.

With 9g of fibre per 100g, it is substantially more filling than white bread and far less likely to trigger blood sugar spikes. The oats, rye flakes and barley also help slow digestion and the release of carbohydrates into the bloodstream. ‘There are three types of fat – rapeseed oil, palm oil and palm fat – but no emulsifiers,’ says Laura. Soft enough for an enjoyable sandwich but studded with plenty of seeds, making it nutty and substantial, eating it feels comforting rather than punitive.

Health Rating: 7/10

Taste Rating: 7/10

Best white loaf for dieters

Aldi White Sourdough Toasting Loaf, £1.79

This Aldi sourdough is impressive, made from a 30-year-old starter and without added yeast, making it more authentic than the ‘sour-faux’ offered by many supermarkets.

With a pleasingly chewy texture and mild flavour, it makes a good sandwich loaf, sturdy enough to hold generous fillings without being onerous to eat.

‘It has clean ingredients, with no UPFs,’ says Laura. ‘It’s the best of all the white loaves – but it’s still a white bread, with refined flour, meaning much of the fibre-rich bran has been removed.’

Health Rating: 7/10

Taste Rating: 7/10

Good for seeds – but bad for UPFs

Morrisons The Best Oat and Barley Loaf, £1.50

A seeded wholegrain loaf made with a mix of wheat flour, oats and sprouted barley grains, this gives a slower energy release than a white loaf. Both oats and barley contain soluble fibre, or beta-glucans, which can help blunt post-meal blood sugar rises, keeping hunger at bay.

Nutty and soft, with a pleasantly sweet flavour, it makes a satisfyingly hearty sandwich and equally good toast. But, says Laura, a deeper dive into the ingredients list proves disappointing.

‘It contains two different types of sugar, as well as preservatives and emulsifiers,’ she says.

Emulsifiers, commonly found under names such as mono and diglycerides of fatty acids, are additives used to improve bread’s texture and shelf life. ‘Research suggests they interfere with the gut microbiome and the body’s appetite regulation,’ says Laura. ‘Studies have linked diets high in UPFs with weight gain.’

Health Rating: 6/10

Taste Rating: 6.5/10

Watch out for the blood sugar spike

M&S Supersoft Thick White Sliced Bread, 75p

Pillowy soft and comforting, white bread is our favourite, accounting for 71 per cent of Britain’s bread consumption – perhaps unsurprisingly, since research has shown the intense sugar spike triggered by its high glycaemic index can be addictive.

Indeed, this M&S loaf has an almost cake-like fluffiness.

It has the added benefit of some vitamin D and, at 3.6g per 100g, it’s higher in fibre than most sliced-white options.

‘The salt is on the high side, at 1.03g, but it lacks unhealthy additives and emulsifiers,’ says Laura. ‘However, the refined white flour will send your blood sugar soaring, followed by an energy crash which will leave you reaching for the biscuit tin a couple of hours later.’

Over time, these blood sugar spikes can contribute to insulin resistance, a metabolic problem linked to weight gain.

Health Rating: 5/10

Taste Rating: 5/10

Not all wholemeal helps you stay slim

Sainsbury’s Medium Sliced Wholemeal Bread, 75p

Many of us believe wholemeal bread must be healthier – but this Sainsbury’s loaf proves that’s not necessarily the case.

‘It contains caramelised sugar, which manufacturers often use in wholemeal loaves to give them their brown colour,’ says Laura. ‘It also contains emulsifiers, calcium propionate preservative and palm oil – so it’s definitely a UPF loaf and could contribute to weight-gain as a result.’

It also has a faintly caramel flavour, which overpowers sandwich fillings, and a stodgy texture. ‘However, it has more fibre than a white loaf, which is its only saving grace,’ says Laura.

Health: 5/10

Taste: 3/10