Sugar reduction: What to replace when you cut sucrose

A bakery brand reformulated a flapjack to clear the NPM threshold ahead of the 5 January 2026 HFSS advertising deadline. They dropped sucrose by 40% and replaced the sweetness with a stevia and erythritol blend dosed to 0.9x sucrose equivalence. Sensory panel scores held. Six weeks into the shelf-life trial, the bars went stale, cracked along the score lines, and developed surface mould in three of twelve replicates. The reformulation failed. Not because the new sweetener tasted wrong, but because nobody had replaced what sugar was actually doing in the bar.

This is the most expensive misread in UK reformulation right now. Sweetness is the most visible thing sugar contributes to a product, but in most formulations it is not the most important. Teams that approach sugar reduction as a sweetener swap run failed shelf-life trials, fail retailer microbiological specs, or watch their texture claim collapse between pilot and scale-up.

Why sugar reduction is harder in 2026 than it used to be

Three pressures have converged on UK food formulators at the same time. The HFSS advertising restrictions came into force across the UK on 5 January 2026, prohibiting HFSS product advertising on television between 5:30am and 9pm and banning all paid online advertising entirely (ASA regulatory statement). Scotland's promotion and placement rules, which mirror the English regime, come into force on 1 October 2026, applying to businesses with 50 or more employees selling pre-packed food in stores larger than 2,000 sq ft. Underneath both, sugar reduction has shifted from a positioning strategy to a formulation requirement, partly driven by GLP-1 medications shrinking appetite and portion sizes.

The result is that more SKUs are being reformulated faster than at any point since the 2018 sugar levy. Most of those reformulations are still being briefed as "swap the sucrose for a sweetener." Most of the failures trace back to that brief. For more on the regulatory side, the Campden BRI HFSS overview maps the full timeline across the four UK nations.

The six jobs sugar is doing in your product

Sugar, almost always sucrose, sometimes glucose syrup or invert, is a structural ingredient masquerading as a flavour ingredient. In a typical solid food, it is doing some combination of these six things at once.

1. Sweetness. The job everyone briefs around. Replaceable in isolation by intense sweeteners (stevia, sucralose, monk fruit) or bulk sweeteners (allulose, polyols), provided the rest of the system is also rebuilt.

2. Bulk and structure. In a cake, biscuit, or bar, sucrose contributes substantial mass and volume. Remove 30% of the sucrose and you are removing 30% of the dry weight the texture is built around. In solid foods, sugar plays a critical role in texture and functional properties, and the bulk and stabilisation effects cannot easily be replicated with alternative sweeteners. Intense sweeteners contribute almost no bulk. Something else has to fill the volume, typically fibres (inulin, polydextrose, resistant maltodextrin), polyols, or allulose where authorised.

3. Water activity reduction. This is the one most often missed. Sucrose binds free water through hydrogen bonding, lowering aw and suppressing microbial growth. Sucrose concentrations of 65% or higher in syrups suppress vegetative bacterial growth for 12 months or more at room temperature, provided pH stays at or below 4.2. Drop sucrose by 40% in a high-moisture product and aw rises. The shelf-life trial then fails on mould, yeast, or bacterial counts, not flavour.

4. Browning and flavour development. In baked goods, browning is what gives the crust its colour and a substantial share of its flavour. Two reactions are at work: caramelisation (sucrose itself, above around 160°C) and Maillard browning (reducing sugars reacting with amino acids). Sucrose is a non-reducing sugar and does not participate directly in the Maillard reaction, but reducing sugars are produced via thermal hydrolysis of sucrose during baking. Remove the sucrose and you remove both pathways at once. Bakes come out pale, taste flat, and read as "not quite right" on sensory panel without anyone being able to point to why.

5. Texture, moisture retention, and shelf life. Sucrose is hygroscopic. It pulls and holds moisture, keeping bakes soft and chewy across shelf life. It also plasticises starch and protein networks, modifying their glass transition temperature (Tg) and the rate at which products stale. Sucrose acts as both a plasticiser and a humectant, modifying phase transitions of biopolymers, dough viscosity, and water activity. Drop the sucrose, and bakes stale faster, biscuits go hard, and bars dry out.

6. Freeze-point depression and ice crystal control. In frozen desserts, sucrose lowers the freezing point of the water phase and controls ice crystal size. Reduce it and the product freezes harder, scoops badly, and develops grainy texture from larger ice crystals.

Any reformulation that reduces sucrose by more than around 20% has to consciously address at least three of these. Most teams brief for one.

What to actually replace, by job

The substitution logic is system level, not ingredient level. When sugar is reduced, several formulation parameters may shift at once, requiring system-level reformulation rather than a single-ingredient substitution. The practical framework:

For sweetness alone: intense sweeteners (steviol glycosides, sucralose, monk fruit, neotame), dosed to a sucrose equivalence target. Mind the lingering aftertaste, as flavour modulators or masking agents are usually needed above 30% replacement.

For bulk: allulose where you can use it (status caveat below), erythritol, polydextrose, inulin, resistant maltodextrin, or non-functional fibres specifically chosen for the texture system. Each behaves differently. Erythritol gives cooling and re-crystallises in low-water systems. Inulin browns above pH 4 and contributes Maillard products. Polydextrose is more neutral but reads as fibre on label.

For water activity: glycerol is the workhorse humectant, though it adds mouthfeel changes and label complexity. Sorbitol works in confectionery. In high-moisture bakes, the usual move is a combination of humectant, reduced moisture target, and tighter packaging.

For browning: if you have removed the Maillard substrate, you can dose a small amount of a reducing sugar (glucose, dextrose, invert) back in deliberately. Even at 1 to 2% inclusion it restores a meaningful share of crust colour and flavour development without moving the NPM score significantly.

For texture and shelf life: this is usually where most of the work is. Plasticiser systems (polyols, glycerol), reformulated starch ratios, and emulsifier adjustments all play. Expect a two to three week trial cycle just to find the texture envelope before optimising taste.

On allulose specifically. US-based formulation content increasingly treats allulose as the answer. In Great Britain it is not yet that simple. The application for allulose under the GB novel food authorisation process was submitted to the FSA and FSS in June 2021, and remains under assessment. As of May 2026, allulose is not yet authorised and cannot be used in food sold in GB. Current status should be checked directly on the FSA register of regulated product applications before any formulation decision.

What this means for an NPD team running a reformulation brief now

Before you write the next reformulation brief, audit which of the six jobs sugar is doing in the SKU you are reformulating. A flapjack is doing 1, 2, 4, 5. A jam is doing 1, 3. A vanilla ice cream is doing 1, 2, 6. A high-protein yogurt is doing 1 and 3 and partly buffering off-notes.

That audit changes the brief from "find a sweetener at the right sweetness equivalence" to "build a system that hits sweetness, bulk, aw target, and browning." It also changes the shelf-life protocol. A reformulation that has reduced sucrose by more than 20% should be on accelerated shelf-life testing from day one, with microbiological endpoints written into the protocol, not just sensory.

Three other things worth doing on day one. First, model the NPM score across multiple reformulation options in parallel rather than serially. Sucrose reduction interacts with the fibre, protein, and saturated fat scoring lines in ways that can change which option is most efficient to develop. Second, document the rejected substitutions and their failure mode, not just the chosen one. They are the most expensive learning the team will buy. Third, if claim retention matters (high fibre, source of protein, no added sugar), thread the claim requirements through the brief from the start, not at the back end where 80% of the substitution work has already been done.

A note on briefing the rest of the business

The reformulation will only work if procurement, technical, and commercial are aligned on what is being traded. Sugar reduction at scale almost always costs more per kg of finished product than the original formulation, sometimes meaningfully more. If commercial is not briefed, the formulation gets unwound at the margin review meeting six weeks before launch.

The teams getting reformulation right in 2026 are not the ones with the best sweetener. They are the ones treating sucrose as the structural ingredient it actually is, building the replacement system around all six jobs, and pricing the work realistically before the brief is signed off.

Common questions about sugar reduction in UK reformulation

What does sugar do in food formulation besides sweetening?

Sugar contributes six functional jobs: sweetness, bulk and structure, water activity reduction (microbial stability), browning and flavour development, texture and moisture retention, and freeze-point depression. Sweetness is usually the least important to replace in a reformulation that has to hold shelf life and texture.

Can I use allulose in UK food in 2026?

Not yet. Allulose remains under novel food assessment by the FSA following the application submitted in June 2021. As of May 2026, allulose is not authorised and cannot be used in food sold in Great Britain. Status should be checked on the FSA register of regulated product applications before any formulation decision.

What replaces sugar's effect on water activity in a reformulation?

Humectants (typically glycerol or sorbitol), tighter packaging, and a reduced moisture target in the formulation. Drop sucrose by more than 20% in a high-moisture product and the water activity rises; the shelf-life trial will then often fail on mould or yeast counts rather than flavour.

Why do sugar-reduced bakery products go stale faster?

Sucrose is hygroscopic and plasticises starch and protein networks, modifying the glass transition temperature of the system. When sucrose is removed, the bake loses moisture-retention capacity and stales faster. The replacement system has to include a humectant or a polyol to restore the function.

How much does sugar reduction typically cost per kg of finished product?

Almost always more than the original formulation, sometimes meaningfully more. The cost depends on which combination of replacers is used: intense sweeteners are cheap on a sweetness-equivalence basis but offer no bulk; bulk replacers (allulose, polyols, fibres) are more expensive than sucrose by weight. The work is in pricing the replacement system before the brief is signed, not after.

When do Scotland's HFSS rules come into force?

Scotland's Food (Promotion and Placement) (Scotland) Regulations 2025 come into force on 1 October 2026. They apply to businesses with 50 or more employees selling pre-packed food in stores larger than 2,000 sq ft, and mirror the existing rules in England.

This is the anchor piece in Nibblr's sugar reformulation series. Coming next: allulose in UK food (what's permitted today and what's pending), Scotland's October 2026 HFSS rules in practice, and the NPM free sugars calculation challenge. Sign up to The Formulation, Nibblr's weekly newsletter, to get the series as it publishes.