Lemon juice, blood sugar and stomach emptying after eating bread
What it found
In ten healthy men, drinking lemon juice with bread lowered the blood sugar rise by about a third compared to water.
It also increased stomach fluid volume and sped up stomach emptying.
What they found
Studies in people
Blood sugar response
At 55 minutes after the meal, blood sugar was 35% lower when the men drank lemon juice instead of water. The overall blood sugar rise in the first 85 minutes was about 40% lower with lemon juice.
Stomach fluid volume
Thirty minutes after eating, the volume of stomach contents was 1.5 times larger with lemon juice than with water (454.0 mL compared to 298.4 mL). The authors suggest this extra volume came from increased digestive fluids rather than slower emptying.
Stomach emptying speed
The stomach emptied 1.5 times faster with lemon juice than with water. Despite starting with more fluid, the stomach finished emptying at about the same time for all three drinks.
Tea had no effect
Black tea made no difference to blood sugar levels, stomach volumes, or emptying speed compared to plain water.
Appetite feelings unchanged
Feelings of hunger, fullness, and thirst were about the same after all three meals. The different stomach volumes and blood sugar levels did not change how hungry or full the men felt.
What the authors conclude
- They conclude that lemon juice lowers the blood sugar rise after eating bread by increasing stomach fluids and speeding up emptying, rather than slowing it down.
- They suggest the acid in lemon juice likely stops a mouth enzyme from breaking down starch early in digestion.
- The authors note that the strong taste of the lemon drink might be hard for most people to accept regularly.
How it was done
Scientists already knew that acidic foods can lower the blood sugar rise after starchy meals, but they did not know exactly how this works. They wanted to see what happens in the stomach at the same time as measuring blood sugar and appetite.
Ten healthy men each ate 100 g of white bread for breakfast on three separate mornings. With the bread they drank either water, black tea, or lemon juice mixed with water. Researchers used MRI scans and finger-prick blood tests over 180 minutes to track stomach contents and blood sugar.
What it can’t tell you
- Only ten men took part, so scientists do not yet know if women or larger groups would respond the same way.
- The study only looked at one breakfast of white bread, so these results may not apply to other meals or longer periods of eating.
Who paid
- Authors work at
- Université Paris-Saclay, France; Teagasc Food Research Centre, Ireland; CEFRED (Centre d'exploration Fonctionnelle et de Rééducation Digestive), France
The paper
- Title
- Glycemic response, satiety, gastric secretions and emptying after bread consumption with water, tea or lemon juice: a randomized crossover intervention using MRI
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Freitas D, Boué F, Benallaoua M, et al (2022). Glycemic response, satiety, gastric secretions and emptying after bread consumption with water, tea or lemon juice: a randomized crossover intervention using MRI. European journal of nutrition. doi:10.1007/s00394-021-02762-2Free full textPubMed 35013789DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error