Watermelon

Watermelon is the fruit whose level surprises people most, because it is almost all water. The concentration is modest; the problem is that nobody eats a small portion of watermelon. It also carries fructans as well as excess fructose, which is unusual for a fruit. The sugars behind this were measured on this fruit, in a study of four - peach, apple, watermelon and cherry - by HPLC. What it settles for this axis is presence and absence rather than a level: sorbitol was found in peach, apple and cherry and not in watermelon, and sucrose in peach, apple and watermelon and not in cherry. It publishes ranges across the four, never a value for one, so it cannot set a FODMAP level by itself.

Watermelon carries fructans as well as excess fructose, which is unusual for a fruit - most fruit brings sugar to this diet, not chains. The fructans are why the FODMAP level does not fall as far as the modest sugar content alone would suggest.

Watermelon is mostly water, which misleads people - but what sugar it has runs fructose-heavy, and nobody eats a small portion of watermelon. The volume is the problem, not the concentration. The sugars here were separated and measured rather than looked up: across the four fruits in that study - peach, apple, watermelon and cherry - fructose ran 5.79 to 104.01 mg per gram, glucose 9.25 to 99.62 and sucrose 15.82 to 106.39. Those are RANGES across four fruits, not a value for this one, which is the honest limit of what an abstract gives. Muir names the watermelon among five fruits of 41 measured with more fructose than glucose; the study publishes no figure for it, only that it belongs to that group.

Watermelon is a mild liberator eaten in the largest portions of any fruit here - nobody has a small piece of watermelon. It is also the melon most often bought halved and clingfilmed, which means it was cut in the shop rather than at home. Volume and cut time, both against it. The Swiss list, which marks L on everything it holds to be a liberator, rates “watermelon” 1 of 3 without that letter. A per-entry rating cannot see either the portion or how long ago the fruit was cut.

Mostly water, so the salicylate per gram is low. Servings are large, which is the only thing that makes it worth watching at all.

Watermelon carries sucrose - it is one of the three fruits in which it was measured, on a range of 15.82 to 106.39 mg per gram across the four studied. A range over four fruits is not a value for one of them; the measurement settles that it is there, not how much.

The watermelon's answer here rests on a measurement rather than on an absence of data, which is rare on this axis: in the study behind it, sorbitol was found in peach, apple and cherry and NOT in watermelon. That is what separates it from the stone fruits it sits beside in a fruit bowl - they carry sorbitol and it does not.