Sugar vs Carbs: What’s the Difference for Blood Sugar?
Sugar vs Carbs:
What’s the difference
for blood sugar?
For carbohydrate awareness, check carbohydrate first—then your portion. Sugars and starch can both affect blood glucose. Fibre is different, and UK and US labels count it differently. Here’s how to make sense of the whole label.
What actually counts as carbohydrate?
Carbohydrates are a family of nutrients. Starch is broken down into glucose during digestion, and sugars can also raise blood glucose. Fibre isn’t digested in the small intestine in the same way. [1] [4]
Sugars
Present naturally in foods such as milk and fruit, and added to other foods. A UK label’s “of which sugars” line includes both. [2]
Starch
Found in foods such as bread, potatoes, rice and pasta. A savoury food can contain little sugar but still provide plenty of carbohydrate. [3]
Fibre
A type of carbohydrate in food science, but listed separately from carbohydrate on UK nutrition panels. That distinction is why online advice can seem contradictory. [4]
Food examples, not separate food groups: many foods contain more than one type of carbohydrate. Fruit also provides fibre; oats and pulses contain starch as well as fibre.
Low sugar doesn’t automatically mean low carbohydrate.
Think of a bowl of plain rice or pasta. Neither needs to taste sweet to contain carbohydrate: starch is carbohydrate too, and your body breaks it down into glucose. Checking only “of which sugars” can therefore miss much of what is on your plate. [3] [5]
Basmati rice
Figures from the published Tesco product label, cooked according to its instructions. [17]
Penne pasta
Figures from the published Tesco product label, cooked according to its instructions. [18]
Starch can raise blood glucose too.
It doesn’t have to taste sweet. The starch in rice, pasta, potatoes and bread is made of long chains of glucose. Digestion breaks those chains apart, releasing glucose into your bloodstream. [19]
STARCH→Enzymes break the chains
GLUCOSE→Glucose is absorbed
BLOOD SUGAR CAN RISE
Is starch always slower than sugar?
No—the food and meal matter. Starch needs breaking down first, but that doesn’t guarantee a slow rise. [15] [20]
White bread & sugary drinks
Ordinary white bread can be digested quickly. Sugary drinks are often absorbed quickly too.
Pasta, pulses & whole fruit
Pasta and pulses tend to release carbohydrate more slowly. Whole fruit brings fibre and a different food structure.
Check the amount as well as the type. Portion size, processing, cooking and the rest of the meal all influence the response. Fibre and polyols behave differently.
The sugars are already inside the total.
In the rice example, 0.1g sugars is part of 32.6g carbohydrate—not an extra amount to add. Most of the remaining carbohydrate is starch. The same principle applies to savoury foods such as potatoes, crackers and ordinary bread. “No added sugar” also doesn’t tell you how much starch a food contains. [2] [3]
Photos illustrate the foods; they do not measure the stated portions. These are specific product examples, not fixed values for all rice or pasta. Check your own pack and whether its figures refer to dry or cooked weight.
Turn the loaf over. Read the whole panel.
Start with the portion and carbohydrate row, then read sugars, polyols and fibre in context. The remaining nutrients and ingredients still matter.
| Typical values | Per 100g | Per 20g slice |
|---|---|---|
| Energy | 897 kJ 216 kcal |
179 kJ 43 kcal |
| Fat | 9.0g | 1.8g |
| of which saturates | 1.0g | 0.19g |
| Carbohydrate | 3.6g | 0.7g |
| of which sugars | 0.9g | 0.2g |
| of which polyols ↓ | 0.3g | <0.1g* |
| Fibre ↓ | 14.8g | 3.0g |
| Protein | 22.2g | 4.4g |
| Salt | 0.92g | 0.2g |
| Net carbs† ↓Supplementary website calculation | 3.3g | 0.7g |
Average values from the SRSLY product information. *0.3g polyols per 100g works out at approximately 0.06g per 20g slice, shown here as less than 0.1g.
†“Net carbs” is a supplementary calculation, not a separately defined nutrient in the UK nutrition declaration: 3.6g carbohydrate − 0.3g polyols = 3.3g per 100g. Per 20g slice: 0.66g, rounded to 0.7g. Fibre is already excluded from UK carbohydrate. How this works →
Ingredients
Water, WHEAT GLUTEN, EGG, Brown Flaxseed, OAT Fibre, Rapeseed Oil, WHEAT Flour (with Calcium, Iron, Niacin, Thiamine), Yeast, Yeast Activator: Inverted Sugar Syrup, Salt, Thickener: Xanthan Gum, Sweetener: Erythritol, Flour Treatment Agent: Ascorbic Acid, Preservative: Calcium Propionate.
Sugars sit inside carbohydrate.
Here is the loaf’s carbohydrate per 100g. Sugars and polyols are included within the 3.6g total.
0.9 + 0.3 + 2.4 = 3.6g. The remainder is calculated from the published figures; it is not a separately measured starch value. Fibre is outside this bar. Why fibre is separate on a UK label →
Educational recreation of the full nutrition and ingredients panel, using published SRSLY information—not a photograph of a printed pack. Always check the pack you receive. Supplementary “net carbs” wording is explained below →, separately from the standard nutrition table.
What are polyols?
Polyols are sweeteners also called sugar alcohols, such as erythritol, maltitol, sorbitol and xylitol. They are different from ordinary sugars. [9]
Included in UK carbs
Polyols sit within the declared carbohydrate figure. The “of which sugars” line excludes them. A sugar-free food can therefore still contain carbohydrate. [4]
Not all absorbed alike
Absorption and effects differ between polyols. Don’t treat all of them as zero carbohydrate or apply a blanket deduction for diabetes management. [9]
Consider your digestion
Larger amounts can cause bloating, wind or diarrhoea in some people. Tolerance varies with the person, amount and type. [9]
Our loaf uses erythritol—what does the evidence say?
EFSA found limited but consistent human evidence that erythritol does not affect blood glucose, with no long-term studies in that evidence set. That doesn’t establish the glucose response to a finished food containing it. [11]
“Sugar alcohol” is the chemical family name; polyols don’t contain the drinking alcohol found in wine or spirits. [10]
Why does our loaf page also show “net carbs”?
The published per-100g figures show this calculation:
The loaf’s 14.8g fibre is already excluded from UK carbohydrate.
Our website subtracts the listed polyols. It is supplementary wording, not a separately defined UK nutrient. [4]
Counting carbs for insulin? Ask your diabetes team how to handle polyols; don’t apply a blanket deduction. [9] Read Net Carbs Explained →
Same idea. Different label systems.
Fibre is present in the food in both countries. What changes is whether it is included in the labelled carbohydrate total. UK and EU-style panels exclude it; US Nutrition Facts includes it. [4] [7]
Carbohydrate excludes fibre.
Don’t subtract the 5g fibre again. It has already been left out of the carbohydrate figure.
Total Carbohydrate includes fibre.
That is why some US “net carb” calculations subtract fibre. The printed US total itself still includes it.
Using these figures for carb counting or comparing labels?
This is an explanation of fibre accounting, not an insulin calculation or a compliant US label conversion. Analytical methods and rounding can differ.
The ADA advises checking US Total Carbohydrate first. Don’t assume a marketing “net” calculation is your clinical carb-counting method. [8]
Why sugar still matters.
Carb awareness doesn’t make sugars irrelevant. UK guidance focuses on reducing free sugars: added sugars, plus those in honey, syrups, juices and smoothies. Sugars in intact fruit and plain milk aren’t classed as free sugars, although they still count in total sugars on the label. [2]
Check the ingredients.
A UK “of which sugars” figure doesn’t separately identify added sugars. Look for ingredients such as sugar, honey or syrup alongside the full panel.
Think about what comes with it.
Whole fruit, pulses, vegetables and wholegrains can bring fibre and other nutrients. Portion size still matters; the lowest-carb food isn’t automatically the best overall choice. [1]
Fibre and protein matter too.
Our sliced loaf brings fibre and protein before you add toppings. Try these two recipes to see how the whole meal adds up; the recipe figures include all the stated ingredients, while the loaf figures below are per slice.
Made with SRSLY sliced breadBonfire Beans on Toast≈12.4g fibre per complete recipe servingView recipe →Fibre: support your digestion.
For digestion: fibre helps food and waste move through the gut and can help prevent constipation.
For meal balance: some types can slow carbohydrate absorption. Try vegetables, fruit, pulses, oats, nuts and seeds.
Made with SRSLY sliced breadHigh-Protein Japanese Egg Sando≈27g protein per complete sandwichView recipe →Protein: help maintain muscle.
For muscle: protein supports the maintenance and repair of muscle and other tissues.
For a satisfying meal: including protein foods can help you feel fuller.
Try eggs, fish, plain yoghurt or tofu. Beans and lentils bring fibre too. [22] [23]
These figures come from the loaf’s published average nutrition values. Fibre and protein don’t cancel carbohydrate or guarantee a particular glucose response. Look at the full meal, including energy, saturated fat and salt, and follow any individual dietary advice from your healthcare team. [6] [15]
One slice. Three simple layers.
Start with our sliced loaf, add creamy avocado, then a poached egg. Here’s how the carbohydrate adds up as you build your plate.
Start with toast
1 slice SRSLY bread · 20g
0.7g carbohydrate
Toast the slice. Its carbohydrate amount stays the same when you toast it.
Add avocado
½ small avocado · 50g flesh
+ about 1.0g carbohydrate
Mash or slice the avocado onto your toast. Weigh the flesh: avocado sizes vary.
Top with an egg
1 large poached egg
+ a trace of carbohydrate
Poach in water and place on top. Herbs and pepper add flavour; count extra sides or sauces.
For the complete example: one 20g slice of SRSLY toast + 50g avocado flesh + one large poached egg. This is UK carbohydrate, without any further fibre or polyol deductions.
How we calculated the meal’s carbohydrate
Estimated nutrition for the stated ingredients and weights: bread 3.6g/100g × 20g = 0.72g; avocado 1.9g/100g × 50g = 0.95g; egg = trace. About 1.67g before rounding, plus the trace amount in the egg. Avocado varieties, egg size and portions vary. The 50g flesh is our example portion for half a small avocado, not a fixed weight for every fruit. No butter, oil, sauce, drink or side is included. Images illustrate the meal stages; weigh your ingredients for the calculation. [6] [13] [14]
Why add egg and avocado?
Egg: adds protein.
Avocado: adds fat and fibre.
Together with carbohydrate, protein, fat and fibre can slow digestion and absorption, which may soften the early glucose rise. [15]
Slower doesn’t mean cancelled.
Toppings don’t remove carbohydrate or guarantee a lower overall glucose response.
Larger amounts of fat and protein can cause a later, longer rise, especially in type 1 diabetes. Follow your diabetes team’s advice if you use insulin. [16]
Choose a portion that suits your appetite and needs. Add vegetables or salad if you like, and include their carbohydrate in your meal total. Energy, saturated fat and salt still matter alongside carbs.
More low-carb meals to make.
Keep familiar favourites in the mix. Each recipe has its own portions and nutrition information; the 1.7g example above applies only to this toast, avocado and egg combination.
Browse all low-carb recipes → · Explore the sliced loaf · Read the fibre guide
Turn the pack over. Take four steps.
Check the UK carbohydrate row, not sugars alone.
Use the weight or number of items you’ll eat.
UK fibre is already excluded. US Total Carbohydrate includes it.
Read polyols, fibre, protein, fats, salt and ingredients too.
Sources and further reading
This UK-focused guide draws on established guidance and label definitions. The linked American Diabetes Association article is a useful introduction, but its US labelling terminology needs the UK distinction explained above. No organisation listed here is endorsing SRSLY or this article.
View all 23 sources
- American Diabetes Association: Sugar vs. Carbs — original reading recommendation, published 20 July 2026; written for US readers.
- NHS: Sugar—the facts — total and free sugars.
- NHS: Starchy foods and carbohydrates.
- Food Information to Consumers Regulation, Annex I — carbohydrate, sugars, fibre and polyol definitions; see also GOV.UK nutrition legislation information.
- Diabetes UK: Understanding food labels.
- SRSLY sliced bread: nutrition and ingredients. Product values are averages; check your pack.
- FDA: Total Carbohydrate — US fibre and sugar alcohol inclusion.
- American Diabetes Association: Reading Food Labels — US Total Carbohydrate and marketing terms.
- Diabetes UK: Sugar, sweeteners and diabetes — polyols and individual advice.
- FDA: Sugar alcohols.
- EFSA: Re-evaluation of erythritol — evidence and limitations.
- Diabetes UK: Low-carb diet and meal plan — getting healthcare support.
- Tesco Hass avocado nutrition — UK carbohydrate 1.9g per 100g; used only as the illustrative avocado input.
- British Lion Eggs: Egg nutrition information — trace carbohydrate; poached without added ingredients.
- Diabetes UK: Glycaemic index and diabetes — protein, fat, fibre and carbohydrate absorption.
- Cambridge University Hospitals: Managing high fat and high protein meals — delayed glucose effects in type 1 diabetes; general guidance, not a study of this meal.
- Tesco Basmati Rice nutrition — cooked values: 32.6g carbohydrate and 0.1g sugars per 100g. Accessed 30 October 2026.
- Tesco Penne Pasta Quills nutrition — cooked values: 31.5g carbohydrate and 0.7g sugars per 100g. Accessed 30 October 2026.
- NHS MyHealth London: Carbohydrates — starch digestion into glucose.
- UCLH: What is the glycaemic index? — starch type, processing, cooking and mixed meals.
- NHS: How to get more fibre into your diet — digestion and the UK adult 30g recommendation.
- NHS: Eating a balanced diet — protein, growth and repair.
- British Heart Foundation: Protein—how much do you need? — muscle maintenance and feeling fuller.