Icing: three ingredients, studied separately

Nobody has ever run a study on icing. What exists is research on the three things it is made of, and putting them together is a calculation rather than a measurement. Sugar first. Pooling 30 trials and 38 cohort studies, eating less sugar moved weight by 0.80 kg and eating more moved it 0.75 kg the other way. Swapping sugar for other carbohydrates at the same calories moved weight by 0.04 kg, which is nothing. The change runs through calories. That is why a sugar-free icing with the same energy has no weight story to tell, and Europe refused exactly that claim for aspartame.

What a real portion looks like

• The American regulator states that how long and how often teeth meet sugar matters more than the size of the serving. — — Evidence E source
  The rule names sucrose as one of the most cariogenic sugars, says oral bacteria metabolise most dietary carbohydrates into acid and plaque, and ties risk to frequency and duration of exposure

What cooking and storage change

• Which fat the buttercream is beaten from changes the blood result: the more trans fat in the hardened fat, the smaller and denser the LDL particles. — 18 women and 18 men eating semiliquid margarine (0.6 g trans per 100 g fat), soft margarine (9.4 g), shortening (13.6 g), stick margarine (26.1 g) or butter (2.6 g trans but high in saturated fat) (n = 36) Evidence B source
  LDL particle size fell in a dose-dependent way as dietary trans fatty acids rose (P < 0.001) compared with the butter diet, and cholesterol in large and medium LDL particles rose in proportion to trans fat intake

What it does to your health

• Cutting sugar shifted weight by under a kilogram, and swapping sugar for other carbohydrates at the same calories shifted nothing at all. — adults and children; 30 eligible trials out of 7895 screened and 38 cohort studies out of 9445 (n = 68 studies) Evidence A source
  In adults eating freely, lower sugar intake gave -0.80 kg (95% CI 0.39 to 1.21, P<0.001) and higher intake +0.75 kg (0.30 to 1.19, P=0.001); isoenergetic exchange of sugars for other carbohydrates gave 0.04 kg (-0.04 to 0.13); trials in children showed no change because compliance with advice was low; in cohorts the odds of overweight or obesity with the highest intake of sugar sweetened beverages were 1.55 (1.32 to 1.82)
• Keeping free sugars under a tenth of daily energy went with fewer cavities, and the evidence for the stricter five percent line is much weaker. — 55 eligible studies from 5990 papers: 3 intervention, 8 cohort, 20 population and 24 cross-sectional, in children and adults (n = 55 studies) Evidence C source
  42 of 50 studies in children and 5 of 5 in adults reported at least one positive association between sugars and caries; moderate quality evidence that caries is lower below 10% of energy from free sugars; at the 5% cut-off the relationship held but the evidence was judged very low quality

What people believe that the data does not support

• Europe allows sweetener makers to say a swap keeps tooth mineral in place, so the dental half of the sugar-free promise has regulatory backing. — — Evidence E source
  Status Authorised for xylitol, sorbitol, mannitol, maltitol, lactitol, isomalt, erythritol, sucralose, polydextrose, D-tagatose and isomaltulose
• The weight-control half of the same promise was refused: Europe would not let aspartame be sold as help with weight management in place of sugar. — — Evidence E source
  Status Non-authorised

Who this works differently for

• A mix of artificial colours with sodium benzoate made ordinary children more hyperactive in a double-blind trial, with a small effect size. — 153 three-year-old and 144 eight-to-nine-year-old children from the general community, not a clinical sample (n = 297) Evidence B source
  Mix A worsened the global hyperactivity aggregate in three-year-olds by 0.20 (95% CI 0.01-0.39, p=0.044), and by 0.32 (0.05-0.60, p=0.02) among those who drank more than 85% of the juice; in eight-to-nine-year-olds mix A gave 0.12 (0.02-0.23, p=0.023) and mix B 0.17 (0.07-0.28, p=0.001)

The bottom line

For teeth the swap does have official backing. Europe authorised the claim that sugar replacers help maintain tooth mineralisation. The American regulation on the same subject is worth reading for a different reason. It says risk comes from how often and how long teeth meet sugar. A slice eaten with a meal is a different event from the same slice picked at all afternoon. On the colours, a double-blind trial in 297 ordinary children found a mix of artificial colours with sodium benzoate worsened behaviour ratings, with effect sizes between 0.12 and 0.32. That is small, it came from a drink rather than a food, and it cannot separate the colours from the preservative. It is also the study behind the warning label carried by six colours in Europe. On the fat, the more trans fat a hardened fat contained, the smaller and denser the LDL particles it produced in a 36 person feeding trial. The shortening in that trial had 13.6 g of trans fat per 100 g, which is the old formulation, so a tub bought today is unlikely to match it. For a parent reading this, none of it turns birthday cake into a problem. The two things that are actually actionable are checking the colour list if a child seems to react, and keeping sweet things to mealtimes rather than spread across the afternoon, which is the part the dental evidence is about.

Sources

1. icg-dr-05 · federal regulation, evidence statement
   The more frequent and longer the exposure of teeth to dietary sugars and starches, the greater the risk for tooth decay.
   21 CFR 101.80, health claims: dietary noncariogenic carbohydrate sweeteners and dental caries · checked 2026-09-22
2. icg-dr-03 · randomised controlled crossover feeding trial
   Relative to the LDL particle size observed after consumption of the butter-enriched diet, LDL particle size decreased significantly and in a dose-dependent fashion with increasing amounts of dietary trans FAs (P < 0.001).
   Am J Clin Nutr, 2003 · checked 2026-09-22
3. icg-dr-01 · systematic review and meta-analysis of randomised controlled trials and cohort studies
   In trials of adults with ad libitum diets (that is, with no strict control of food intake), reduced intake of dietary sugars was associated with a decrease in body weight (0.80 kg, 95% confidence interval 0.39 to 1.21; P<0.001); increased sugars intake was associated with a comparable weight increase (0.75 kg, 0.30 to 1.19; P=0.001). Isoenergetic exchange of dietary sugars with other carbohydrates showed no change in body weight (0.04 kg, -0.04 to 0.13).
   BMJ, 2012 · checked 2026-09-22
4. icg-dr-04 · systematic review of intervention, cohort and cross-sectional studies
   There is evidence of moderate quality showing that caries is lower when free-sugars intake is < 10% E. With the < 5% E cut-off, a significant relationship was observed, but the evidence was judged to be of very low quality.
   J Dent Res, 2014 · checked 2026-09-22
5. icg-dr-06 · regulatory register entry
   POL-HC-6466 Sugar replacers, i.e. intense sweeteners; xylitol, sorbitol, mannitol, maltitol, lactitol, isomalt, erythritol, sucralose and polydextrose; D-tagatose and isomaltulose Consumption of foods/drinks containing instead of sugar* contributes to the maintenance of tooth mineralisation * In the case of D-tagatose and isomaltulose this should read ""other sugars"" Authorised
   EU Register on nutrition and health claims, заява POL-HC-6466, знімок 2026-09-21 · checked 2026-09-22
6. icg-dr-07 · regulatory register entry
   POL-HC-6653 Aspartame sucrose substitute Weight control /management is helped by using foods and beverages sweetened with Aspartame in place of foods and beverages sweetened with sugar. Non-authorised
   EU Register on nutrition and health claims, заява POL-HC-6653, знімок 2026-09-21 · checked 2026-09-22
7. icg-dr-02 · randomised double-blind placebo-controlled crossover trial
   Mix A had a significantly adverse effect compared with placebo in GHA for all 3-year-old children (effect size 0.20 [95% CI 0.01-0.39], p=0.044) but not mix B versus placebo.
   Lancet, 2007 · checked 2026-09-22