Short answer: No. A 1995 meta-analysis of double-blind studies found that sugar did not affect children’s behavior or thinking, even in children with attention problems. Parents who expect a sugar effect tend to see one. Steady blood sugar, fewer artificial colours and a better overall diet are more worthwhile than banning sugar.

Diet is not a substitute for the treatment your child’s doctor prescribes. Do not stop or change ADHD medication on the basis of anything here. Only try an elimination or restrictive diet in a child with the help of a doctor or registered dietitian, to avoid nutritional deficiencies.

Sugar does not cause ADHD and does not make children hyperactive, according to decades of controlled trials. The evidence is moderate: the trials were double-blind, though small and short. A small effect, or an effect in a few children, can’t be ruled out.

What does seem to matter is the wider diet. Large blood sugar swings, heavily processed food and artificial colours may play a part, and some children react to specific foods. For what to put on the plate instead, see best foods for ADHD. Adults with ADHD can find practical advice in our guide for adults.

What the double-blind trials found

The key evidence is a meta-analysis by Wolraich and colleagues, published in JAMA in 1995. The researchers pooled 23 studies from 16 reports. In each, children, parents and researchers were all blinded to whether the child got sugar or an artificial-sweetener placebo. The studies included children whose parents called them sugar-sensitive and children with attention deficit disorder.

Sugar did not affect the behavior or cognitive performance of children. Across 14 behavioral and cognitive measures, the 95% confidence interval for every pooled effect included zero. The authors added that a small effect, or effects in some children, could not be ruled out, because the individual studies were small and short-term.

One of the most careful single studies (Wolraich 1994) followed 25 typical preschool children and 23 school-age children whose parents described them as sugar-sensitive. Each family went through three three-week diets: one high in sucrose, one sweetened with aspartame and one with saccharin as a placebo. All three diets were essentially free of additives and artificial colourings.

For the sugar-sensitive children, there were no significant differences among the diets on any of 39 behavioral and cognitive measures. For the preschool children, 4 of 31 measures differed, with no consistent pattern. The children whose parents were most certain they reacted to sugar did not react to it.

These studies included the children most likely to show an effect, and they were double-blind, which removes observer bias. A large effect of sugar on behavior would very likely have shown up.

Why parents still see a sugar effect

Expectations change what parents see

In a study by Hoover and Milich (1994), 35 boys aged 5 to 7 whose mothers called them sugar-sensitive all got the same aspartame-sweetened drink. Half the mothers were told their son had a large dose of sugar. The other half were told, correctly, that he had aspartame.

Mothers who thought their son had sugar rated him as significantly more hyperactive, although every child had the same drink. Video recordings showed these mothers also behaved differently. They stayed physically closer to their sons, and tended to criticize, look at and talk to them more. Their expectations changed how they treated their children, not only how they rated them.

Sugar comes with exciting events

Children eat most sugar at birthday parties, Halloween and holidays. These events are exciting in their own right, full of other children and often involve late nights. A child who is wild at a party is reacting to the party, not the cake.

People also notice and remember cases that fit their belief (cake, then chaos) more than cases that don’t (cake, then calm). Psychologists call this an illusory correlation.

Sugar itself may not cause hyperactivity, but sugar-heavy eating affects blood glucose. Some studies find that thinking slows when blood sugar falls a few hours after a meal. It is plausible that such dips add to ADHD symptoms, but this has not been tested directly in children with ADHD. Our article on blood sugar and brain function covers the mechanisms.

One small study found no unusual blood sugar response in children with attention problems. In it (Girardi 1995), 17 children with attention deficit disorder and 11 controls drank a standard glucose drink. Blood glucose and insulin responses were similar in both groups, including the late fall three to five hours later. The children with ADD did not show more reactive hypoglycemia (a sugar crash). Their adrenaline response to the late fall was about half that of controls. Attention test performance worsened in both groups as glucose fell.

Breakfast may matter. In a crossover study of 64 children aged 6 to 11 (Ingwersen 2007), attention and memory declined less after a low-GI cereal than after a high-GI cereal. The glycemic index (GI) ranks how fast a food raises blood sugar. The children were not selected for attention problems, and individual responses to food vary a lot.

Overall diet matters more than sugar alone

Studies that look at whole eating patterns find links with ADHD, though none can show cause and effect:

  • A cross-sectional study of 986 Korean children (Park 2012) found that high intake of sweetened desserts, fried food and salt was associated with more learning, attention and behavioral problems. Regular meals, a balanced diet, and more dairy and vegetables were associated with fewer.
  • In 1,799 Australian adolescents (Howard 2011), a “Western” eating pattern was associated with about twice the odds of an ADHD diagnosis.
  • A meta-analysis of 14 observational studies (Del-Ponte 2019) found that “unhealthy” patterns, high in refined sugar and saturated fat, were associated with higher odds of ADHD. “Healthy” patterns, high in fruit and vegetables, were associated with lower odds. The authors called the evidence weak.
  • A Taiwanese case-control study of 173 children with ADHD and 159 without (Yu 2016) found higher odds of ADHD with higher intake of sugar-sweetened drinks. This design cannot show which came first.

These links come from whole diets, not from sugar alone. White bread, white rice and breakfast cereals raise blood sugar about as much as table sugar, or more. The fix is a better overall pattern, not just less sugar.

Artificial colours may be the real culprit

Brightly coloured sweets and drinks often contain artificial colours, and these have better evidence than sugar. In the Southampton study (McCann 2007), mixtures of artificial food colours and the preservative sodium benzoate increased hyperactivity. This held in 3-year-olds and 8/9-year-olds from the general population, not just children with ADHD. The study helped prompt the European Union to require warning labels on foods with certain artificial colours.

So a parent who sees hyperactivity after colourful sweets may be right that the food played a part. The likelier culprit is an artificial colour, or the processed food as a whole, rather than the sugar.

Some children react to specific foods, usually not sugar

The INCA trial (Pelsser 2011) included 100 children aged 4 to 8 with ADHD. They were randomized to a very restricted “few foods” diet (rice, meat, vegetables, pears and water) or to advice on healthy eating. After five weeks, 64% of children on the restricted diet had at least a 40% drop on an ADHD rating scale. Only the assessing paediatrician was blinded in this phase; parents knew what their children were eating. When foods were reintroduced double-blind, symptoms returned in 19 of 30 responders (63%).

Foods were reintroduced one by one for each child, so the trial points to no single trigger, and it did not test sugar. The authors advised against choosing foods to remove using IgG blood tests. A later meta-analysis (Sonuga-Barke 2013) found that when only probably-blinded raters were counted, the effect of elimination diets was no longer statistically significant. Removing artificial colours and taking fatty acid supplements stayed significant. More on elimination diets is in best foods for ADHD.

What to do instead of banning sugar

  1. Stop blaming sugar alone. Fixating on sugar distracts from changes that matter more and can make eating stressful for children.
  2. Aim for steady blood sugar. Build meals around protein, healthy fats and fiber-rich carbohydrates. Eggs with whole-grain toast and avocado may sustain attention better than sugary cereal with juice.
  3. Swap refined foods for whole ones. Whole-grain for white bread, oats for sugary cereal, whole fruit for juice, nuts and vegetables for packaged snacks. Replace soft drinks and juice with water, milk or unsweetened drinks.
  4. Cut artificial colours. Read labels and reduce artificial colours, flavors and preservatives, especially for children.
  5. Consider a supervised elimination diet only if symptoms warrant it. For moderate to severe ADHD that hasn’t responded to other treatment, a few-foods diet with a doctor and registered dietitian may identify individual sensitivities. Never try a restrictive elimination diet in a child without that support.
  6. Watch for the expectancy effect. Ask whether excitement, poor sleep or a busy setting better explains the behavior you see.

Frequently asked questions

Should I still limit my child’s sugar?

Yes, for general health: teeth, metabolic health, obesity risk and crowding out better food. What the evidence does not support is limiting sugar specifically because of ADHD or hyperactivity.

Why are sugary drinks worth singling out?

They cause some of the sharpest blood sugar spikes of any food, contain no fiber or protein to slow absorption, often carry artificial colours, and replace more nutritious drinks. That makes swapping them for water or milk an easy, well-supported change.

Sources

  • Del-Ponte, B., et al. (2019). Dietary patterns and attention deficit/hyperactivity disorder (ADHD): A systematic review and meta-analysis. Journal of Affective Disorders, 252, 160-173. doi:10.1016/j.jad.2019.04.061
  • Girardi, N. L., et al. (1995). Blunted catecholamine responses after glucose ingestion in children with attention deficit disorder. Pediatric Research, 38(4), 539-542. doi:10.1203/00006450-199510000-00011
  • Hoover, D. W., & Milich, R. (1994). Effects of sugar ingestion expectancies on mother-child interactions. Journal of Abnormal Child Psychology, 22(4), 501-515. doi:10.1007/BF02168088
  • Howard, A. L., et al. (2011). ADHD is associated with a “Western” dietary pattern in adolescents. Journal of Attention Disorders, 15(5), 403-411. doi:10.1177/1087054710365990
  • Ingwersen, J., et al. (2007). A low glycaemic index breakfast cereal preferentially prevents children’s cognitive performance from declining throughout the morning. Appetite, 49(1), 240-244. doi:10.1016/j.appet.2006.06.009
  • McCann, D., et al. (2007). Food additives and hyperactive behaviour in 3-year-old and 8/9-year-old children in the community: A randomised, double-blinded, placebo-controlled trial. The Lancet, 370(9598), 1560-1567. doi:10.1016/S0140-6736(07)61306-3
  • Park, S., et al. (2012). Association between dietary behaviors and attention-deficit/hyperactivity disorder and learning disabilities in school-aged children. Psychiatry Research, 198(3), 468-476. doi:10.1016/j.psychres.2012.02.012
  • Pelsser, L. M., et al. (2011). Effects of a restricted elimination diet on the behaviour of children with attention-deficit hyperactivity disorder (INCA study): A randomised controlled trial. The Lancet, 377(9764), 494-503. doi:10.1016/S0140-6736(10)62227-1
  • Sonuga-Barke, E. J. S., et al. (2013). Nonpharmacological interventions for ADHD: Systematic review and meta-analyses of randomized controlled trials of dietary and psychological treatments. American Journal of Psychiatry, 170(3), 275-289. doi:10.1176/appi.ajp.2012.12070991
  • Wolraich, M. L., et al. (1994). Effects of diets high in sucrose or aspartame on the behavior and cognitive performance of children. The New England Journal of Medicine, 330(5), 301-307. doi:10.1056/NEJM199402033300501
  • Wolraich, M. L., Wilson, D. B., & White, J. W. (1995). The effect of sugar on behavior or cognition in children: A meta-analysis. JAMA, 274(20), 1617-1621. doi:10.1001/jama.1995.03530200053037
  • Yu, C. J., et al. (2016). Sugar-sweetened beverage consumption is adversely associated with childhood attention deficit/hyperactivity disorder. International Journal of Environmental Research and Public Health, 13(7), 678. doi:10.3390/ijerph13070678

This article is for educational purposes only and does not constitute medical advice. Consult a qualified healthcare professional before making significant dietary changes or starting supplementation, especially for children or individuals taking medication.