Oats

Researchers in Chicago carried out a randomized, double-blind, controlled clinical trial of ninety-seven men and women, in which half of the group consumed foods containing oat beta-glucan, while the other half ate control foods. At the end of the trial period, the oat group showed improvements in insulin sensitivity, while the control group was unchanged.
European Journal of Clinical Nutrition, June 2007; 61(6):786-95

A University of Milan study compared buckwheat, oats, and, quinoa to see if any of them showed promise in helping with appetite control.  In three experiments – one for each grain – subjects’ satisfaction and subsequent calorie consumption were compared, after eating the study grain and after eating wheat or rice. All three study grains had a higher Satiating Efficiency Index (SEI) than wheat or rice; white bread was in fact lowest in appetite satisfaction. Unfortunately, even after feeling fuller from eating the study grains, the subjects did not cut their calories at the next meal!
British Journal of Nutrition, November 2005; 94 (5):850-8.

USDA researchers fed barley flakes, barley flour, rolled oats, oat flour, and glucose to 10 overweight middle-aged women, then studied their bodies’ responses. They found that peak glucose and insulin levels after barley were significantly lower than those after glucose or oats. Particle size did not appear to be a factor, as both flour and flakes had similar effects.
Journal of the American College of Nutrition, June 2005; 24(3):182-8

A team led by Dr. Pauline Koh-Banerjee studied diet and health records of 72,000 men and found that those who ate 40 grams of whole grains per day cut middle-age weight gain by up to 3.5 pounds. Just one cup of cooked oatmeal or two slices of whole-wheat bread would provide this amount of whole grain.
American Journal of Clinical Nutrition, November 2004; vol 80(5):1237-45

Dr. Rui Hai Liu of Cornell and his colleagues discovered that whole grains contain protective antioxidants in quantities rivalling or exceeding those in fruits and vegetables. Corn, for instance, has almost twice the antioxidant activity of apples, while wheat and oats almost equal broccoli and spinach in antioxidant activity.
American Institute for Cancer Research (AICR) International Conference on Food, Nutrition and Cancer, November 2004

Researchers at Colorado State University randomly assigned thirty-six overweight middle-aged men to eat either an oat or wheat cereal daily for twelve weeks. At the end of the three-month period, the men eating the oat cereal had lower concentrations of small, dense LDL cholesterol (thought to be particularly dangerous) and lower LDL overall, compared to those in the wheat group, while their HDL (“good”) cholesterol was unchanged.
American Journal of Clinical Nutrition, August 2002; 76(2):351-8

Using a randomized, controlled parallel-group pilot study, researchers followed 18 hypertensive and hyperinsulemic men and women for six weeks, while half of them ate oat cereal (5.52g/day of beta-glucan) and the others ate a lower-fiber cereal (less than 1g total fiber). The oat group enjoyed a 7.5mm Hg reduction in systolic blood pressure and a 5.5 mm Hg reduction in diastolic blood pressure, while the wheat group was unchanged.
Journal of Family Practice, April 2002; 51(4):369

Also in Australia, researchers at the University of Sydney fed 38 different foods, one by one, to 11-13 different people, then asked them to report their “satiety” or fullness every 15 minutes for the next two hours. From this, they ranked all 38 foods in a “Satiety Index.” Oatmeal rated #3 overall for making people feel satisfied and full, and it rated #1 in the breakfast food group.
European Journal of Clinical Nutrition, September 1995; 49(9): 675-90