The role of dietary fiber in satiety, glucose, and insulin: studies with fruit and fruit juice.
Level 3 - non-randomized controlled study
Non-randomized or unstated-randomization controlled crossover experimental feeding study in humans
PubMed 6259919 · doi:10.1093/ajcn/34.2.211
What was done
Healthy human volunteers consumed sugar-equivalent meals consisting of whole fruit versus fruit juice, testing both oranges versus orange juice and grapes versus grape juice (with additional testing of diluted grape juice). Satiety was evaluated using two subjective scoring systems, and postprandial plasma glucose and insulin concentrations were monitored.
What was found
The abstract reports no absolute numerical values or effect sizes. Subjective satiety was greater and the return of appetite was delayed following whole fruit compared to juice for both fruits. For oranges, the whole fruit resulted in a significantly smaller insulin response and less postabsorptive fall in plasma glucose compared to orange juice. For grapes, whole fruit elicited a higher insulin response than grape juice with similar postabsorptive glucose levels. Diluting grape juice did not increase its insulin response.
Why it matters
The study demonstrates that the physical form and dietary fiber content of fruit alter satiety and metabolic responses independently of total sugar content, though metabolic patterns vary across specific fruit types.
Limits
The abstract does not disclose the sample size, participant demographics, study duration, or exact numerical values with confidence intervals or p-values. Randomization and blinding details are omitted, and satiety was measured solely through subjective scoring systems.
Cited by
- supports Consuming juiced fruit causes a rapid increase in blood sugar and an insulin response that leads to a subsequent blood sugar drop, driving hunger.