Abstract: An onion extract weight gain control composition includes from 20% to 40% by weight of polyphenols belonging to the flavonol family, the onion extract having following composition characteristics, expressed in weight based on the dry extract total weight: from 60% to 90% by weight of the total flavonols in the extract consist in glycosylated polyphenols, from 85% to 98% by weight of the total flavonols in the extract consist in quercetin in a free form (aglycone) or in a glycosylated form, from 5% to 20% by weight of the total flavonols in the extract consist in quercetin-3,4?-diglucoside, from 30% to 70% by weight of the total flavonols in the extract consist in quercetin-3-monoglucoside and quercetin-4?-monoglucoside, and from 20 to 30% by weight of the total flavonols in the extract consist in quercetin.

Abstract: The invention concerns the use of an onion extract comprising 20 wt. % to 40 wt. % of polyphenols of the flavonol family, said onion extract having the following composition characteristics, expressed in weight relative to the total extract dry weight: 60 wt. % to 90 wt. % of the total flavonols of said extract consist of glycosylated polyphenols; 85 wt. % to 98 wt. % of total flavonols of said extract consist of free-form (aglycon) or glycosylated quercetin; 5 wt. % to 20 wt. % of the total flavonols of said extract consist of quercetin-3,4?-diglucoside; 30 wt. % to 70 wt. % of the total flavonols of said extract consist of quercetin-3-monoglucoside and quercetin-4?-monoglucoside; and 20 wt. % to 30 wt. % of the total flavonols of said extract consist of quercetin, for making a composition to control weight gain.