Chrononutrition, or the circadian timing of food intake, proposes that nutrients, bioactive compounds, and foods modulate the peripheral clocks with implications on health. We evaluated the effects of biscuits supplemented with the antioxidant dietary fiber isolated from spent coffee grounds as a food ingredient (SCF-B) or a combination of spent coffee grounds and fructooligosaccharides (SC-FOS-B), and a traditional recipe (TB, without added fiber) on the modulation of circadian rhythm in young adults. The repeated intake (21 days/45 g portion) of SCF-B or SC-FOS-B decreased (p < 0.05) the evening chronotypes. SCF-B and SC-FOS-B consumption enhanced the chronodisruption associated with colonic short chain fatty acid production, thus improving the quality and length of sleep. This is the first study on the positive impact of antioxidant dietary fiber obtained from spent coffee grounds on circadian activity improvement in young adults. Further clinical trials and the role of other bioactive compounds as therapeutic candidates for health disturbances related to circadian dysfunction are necessary to confirm the results.