Syrup: one word, twenty one products, almost no research on the bottle

The word syrup covers 21 different records in the USDA tables on this page, from cane and maple to high fructose corn syrup and chocolate sauce. Almost none of the research is about those table syrups. What has been tested is fructose as an ingredient inside controlled diets, plus two syrups that are products of their own, a flavoured syrup drink and yacon syrup. Swapping fructose or high fructose corn syrup for glucose or sucrose at the same calories changed almost nothing across 25 trials in 1744 people, and a slight fall in diastolic blood pressure was the only movement. Read that carefully. It says one sugar behaves much like another sugar. It says nothing about whether the sugar was worth eating. The ceiling is the part that reaches every syrup on the shelf. WHO counts the sugars already present in syrup as free sugars, the same category as added sugar, and asks for under 10 percent of daily energy. Observational data links that ceiling to disease. In 176 057 UK Biobank adults followed for a median of 11 years, taking more than 12 percent of energy as free sugar went with a higher rate of type 2 diabetes, and 5078 people developed it. That study pooled syrup with every other free sugar and never measured syrup on its own, so it tells you about the category and not about the bottle.

The numbers, per 100 g

What your body absorbs

• In 16 healthy adults, a syrup drink carrying 50 g of carbohydrate peaked at 123.1 mg/dL of blood glucose at 60 minutes against 147.4 for a purpose made carbohydrate drink. Sixteen people over one morning is no basis for reading syrup as gentle on blood sugar. — 16 healthy volunteers aged 18 to 60, randomised crossover with 1 week washout, Thailand (n = 16) Evidence B source
  Glucose peak at 60 min 123.1 mg/dL (SD 22.4) for the syrup drink against 147.4 mg/dL (SD 28.0) for 400 mL and 148.7 mg/dL (SD 21.7) for 250 mL of the novel drink, p = 0.006
• The syrup drink in that trial was 60 mL of flavoured syrup diluted to 250 mL to reach 50 g of carbohydrate, and its osmolality was 365 mOsm/kg against 207 for the purpose made drink. — test beverages of a randomised crossover trial in 16 healthy volunteers (n = 16) Evidence B source
  Syrup drink osmolality 365 mOsm/kg and pH 5.71; comparator 207 mOsm/kg and pH 6.51 at the same 50 g of carbohydrate

What it does to your health

• Swapping fructose or high fructose corn syrup for glucose or sucrose at equal calories changed almost nothing across 25 trials in 1744 volunteers, with only a slight fall in diastolic blood pressure. — 1744 volunteers in 25 controlled isoenergetic dietary intervention trials (n = 1744) Evidence A source
  No significant effect on total, LDL and HDL cholesterol, triacylglycerols, blood pressure, fasting glucose or body weight; slight decrease in diastolic blood pressure for fructose instead of glucose
• Across 6 observational and 21 intervention studies, the evidence was too weak to say whether high fructose corn syrup or sucrose causes fatty liver disease. — children and adults with low to no alcohol intake, 27 studies (n = 27 studies) Evidence A source
  Insufficient evidence for HFCS or sucrose and NAFLD; low level of evidence that a hypercaloric fructose diet raises liver fat and AST in healthy men
• Observational data from 176 057 UK Biobank adults followed a median of 11 years links free sugar above 12% of energy with higher type 2 diabetes risk, and 5078 people developed the disease. Syrup sat inside that category and was never measured on its own. — 176 057 UK Biobank participants, median follow-up 11 years (n = 176057) Evidence C source
  Higher risk above 12%E of free sugar; waist to height ratio explained 31% of the excess risk; substituting free sugar with non-free sugar or plant protein went with 16% lower risk
• Yacon syrup is a separate product and nothing here carries over to maple, cane or corn syrup. Seven clinical trials in 161 participants reported lower fasting insulin, HOMA-IR and LDL cholesterol on it, and the review pooled them without a meta-analysis. Doses and long term safety are not established. — 161 healthy, overweight or obese participants across 7 clinical trials in South America and Europe (n = 161) Evidence B source
  Reductions in fasting insulin, HOMA-IR and LDL cholesterol; improved satiety and intestinal transit; acute effects on postprandial glycaemia inconsistent

Safety, limits and interactions

• WHO counts sugars naturally present in syrups as free sugars, so syrup falls under the same ceiling as added sugar. — adults and children, WHO guideline definition Evidence E source
  Definition, not an effect size: syrups sit inside the free sugars category that the 2015 guideline asks to keep below 10% of energy
• Cough syrup is medicine and a different product from the syrups in the table above. The authors name ethylene glycol contamination of cough syrups as a recognised poisoning route worldwide. Their own patient reached an ethylene glycol level of 188 mg/dL by another route and still had kidney damage 2 months later. — one man in his late 70s with hypertension, United States, a single case involving a medicinal cough syrup (n = 1) Evidence D source
  Ethylene glycol 188 mg/dL, anion gap metabolic acidosis, acute kidney injury, serum creatinine still elevated at 2 month follow-up

What people believe that the data does not support

• A jar of pure maple syrup or honey does not have to print grams of added sugars, yet it must still print the percent Daily Value for added sugars, so a label without the grams line is not a label without added sugar. — single-ingredient packages of pure honey, pure maple syrup and other pure sugars and syrups sold in the United States Evidence E source
  Labelling rule, not an effect size: the grams line may be omitted while the %DV line stays mandatory

What is still unknown

• A 2025 systematic review screened 23 006 records on high fructose corn syrup and liver injury and found exactly 1 study that met its criteria. — adults aged 18 and over with low to no alcohol intake (n = 1 study) Evidence C source
  1 eligible study out of 23 006 retrieved and 16 955 screened; the authors call the scarcity of focused research concerning

The bottom line

If you pour syrup, count it as sugar. That is the part the data supports. One trial adds a smaller detail. A drink made from 60 mL of flavoured syrup diluted to 250 mL, carrying 50 g of carbohydrate, took blood glucose to 123.1 mg/dL at 60 minutes in 16 healthy adults. A purpose made carbohydrate drink with the same 50 g took it to 147.4 mg/dL. The syrup drink was the more concentrated of the two, 365 mOsm/kg against 207. Sixteen people over one morning is a thin basis for anything, and nobody should read it as syrup being gentle on blood sugar. Two things sold under the same word are separate products. Yacon syrup is rich in fructooligosaccharides, and across 7 trials in 161 people it lowered fasting insulin, HOMA-IR and LDL cholesterol. Those results belong to yacon, they do not carry over to maple or corn syrup, and the review that pooled them says doses and long term safety are not established. Cough syrup is medicine. The authors of one case report name ethylene glycol contamination of cough syrups as a poisoning route that matters worldwide. Their own patient, a man in his late seventies, reached a blood level of 188 mg/dL by another route and still had kidney damage two months later. The label can mislead you while following the rules. A jar of pure maple syrup or pure honey sold in the United States may leave the grams of added sugars off the label, and the percent Daily Value line for added sugars stays mandatory. A missing grams line is a rule about single ingredient jars. The sugar is in the jar either way. Now the part we could not tell you. We found no work on how the same syrup varies between batches, seasons and producers, and 21 records under one word suggest that spread is wide. Nothing on what heating or baking does to it. Nothing on what a normal serving looks like in a kitchen rather than in grams. The gap that bothers us most is the question of who should be more careful. We found no card on syrup in pregnancy, in children, in people with kidney disease, or alongside any medicine. Our safety shelf here holds a definition from WHO and one poisoning case, and that falls well short of knowing whether syrup is fine for you in particular. The fatty liver question stays open too. Across 6 observational and 21 intervention studies the evidence was too weak to say whether high fructose corn syrup or sucrose causes fatty liver disease, and a 2025 review screened 23 006 records to find exactly 1 study that qualified.

Sources

1. syr-r3-03 · randomised controlled trial
   Novel carbohydrate drinks produced higher glucose peaks at 60 min (C400: 147.4 mg/dL [28.0]; C250: 148.7 mg/dL [21.7]) than SYR (123.1 mg/dL [22.4], p = 0.006) with sustained elevation through 120 min.
   Nutrients, 2025 · checked 2026-09-23
2. syr-r3-04 · randomised controlled trial
   with 60 mL of syrup diluted to a final volume of 250 mL to achieve 50 g of carbohydrate (pH 5.71, osmolality 365 mOsm/kg)
   Nutrients, 2025 · checked 2026-09-23
3. syr-r3-01 · systematic review and meta-analysis
   Twenty-five studies involving 1744 volunteers were identified. No significant effects were found when fructose or HFCS was substituted for glucose, except for a slight decrease in diastolic blood pressure when fructose was substituted for glucose.
   Nutr Rev, 2021 · checked 2026-09-23
4. syr-r3-02 · systematic review and meta-analysis
   Six observational studies and 21 intervention studies met the inclusion criteria...There was insufficient evidence to draw a conclusion for effects of HFCS or sucrose on NAFLD.
   Am J Clin Nutr, 2014 · checked 2026-09-23
5. syr-r3-05 · prospective cohort
   Over a median follow-up of 11 years, 5078 (2.9%) of the 176,057 participants had development of type 2 diabetes. Higher risk of type 2 diabetes was observed in people with higher intake of free sugar (>12%E; free sugar included any added sugar and sugar in honey, syrup, and juices), starch (>25%E), and animal protein
   Mayo Clin Proc, 2026 · checked 2026-09-23
6. syr-r3-07 · systematic review
   Seven studies met the inclusion criteria, encompassing 161 participants from diverse populations. RESULTS: Yacon syrup supplementation demonstrated significant reductions in fasting insulin, HOMA-IR, and LDL cholesterol, alongside improvements in satiety and intestinal transit time.
   Nutrients, 2025 · checked 2026-09-23
7. syr-r3-08 · guideline
   Free sugars include monosaccharides and disaccharides added to foods and beverages by the manufacturer, cook or consumer, and sugars naturally present in honey, syrups, fruit juices and fruit juice concentrates
   WHO, Guideline: sugars intake for adults and children, 2015 · checked 2026-09-23
8. syr-r3-10 · case report
   Ethylene glycol toxicity poses a significant global health challenge, especially in low-income countries where it contaminates cough syrups.
   BMJ Case Rep, 2026 · checked 2026-09-23
9. syr-r3-09 · agency guidance
   must still include the percent Daily Value for added sugars
   FDA, Guidance for Industry: Declaration of Added Sugars on Honey, Maple Syrup, Other Single-Ingredient Sugars and Syrups, and Certain Cranberry Products · checked 2026-09-23
10. syr-r3-06 · systematic review
    The literature search yielded 23,006 studies. After removing duplicates, 16,955 studies were screened and 16,930 were excluded after abstract screening. 20 texts were reviewed in full; 19 were excluded. 1 study was included after study selection.
    Front Nutr, 2025 · checked 2026-09-23