The extent to which glucose intolerance can be acutely improved with dietary modification is unclear. The purpose of this study was to test the effect of ingesting a low-calorie almond preload ("appetizer") 30 minutes before oral glucose tolerance testing in glucose-intolerant individuals without diabetes. Twenty adults with prediabetes or isolated 1-hour glucose ≥160 mg/dL underwent 2 fasting oral glucose tolerance tests (GTTs)-1 standard GTT and 1 GTT 30 minutes after eating a half ounce (12) of dry-roasted almonds. Fourteen participants met 1 or more prediabetes diagnostic criteria; 6 had only elevated 1-hour glucose ≥160 mg/dL. The mean 1-hour plasma glucose after the almond preload was 37.1 mg/dL (19.4%) lower (154.6 vs 191.7; P < .001) than in the standard GTT. The almond preload reduced the area under the glucose curve by 15.5% (P < .001). Eight individuals had a marked hypoglycemic effect (glucose reduced by 45 to 110 mg/dL); 4 had a moderate hypoglycemic effect (22-32 mg/dL). A low-calorie almond "appetizer" showed promise as an option for decreasing postprandial hyperglycemia in individuals with prediabetes or isolated 1-hour postprandial hyperglycemia. Further study is needed to confirm and refine the role of such a premeal appetizer in the self-care of prediabetes.