poster abstractBackground: The mechanisms that result in greater caloric intake in obese individuals
are incompletely understood. Ghrelin administration increases ad lib food intake in
humans. We investigated the relationship of ghrelin to calorie consumption and hunger
at breakfast on two separate occasions in lean and obese women.
Methods: 23 lean (BMI 22.3±0.5 kg/m2, 26.5±1.0 yr) and 25 obese (BMI 36.9±0.7 kg/m2,
27.8±1.1 yr) women participated in a noncontiguous 2 day study. The minimum and
maximum days between visits were 6 and 43 days. Participants were given the same
breakfast on both days (turkey sausage, French toast with margarine/syrup, fruit cup,
coffee, tea, diet soda, or water) with portions adjusted to provide 20% of the daily energy
requirement for weight maintenance. Subjects were instructed to eat until full. Hunger
was evaluated on a Satiety Labeled Intensity Magnitude Scale (SLIM) before and after
the meal. Anchors were “greatest imaginable fullness” at 0 and “greatest imaginable
hunger” at 100. Blood samples were collected over 120 minutes for measurement of
active ghrelin.
Results: Lean subjects consumed an equivalent number of calories on both days
(380.0±14.6 vs 378.2±14.9 kcal), as did the obese (419.4±16.2 vs 428.8±15.4 kcal). On
average for both days, obese consumed significantly more breakfast calories than lean
(424.1±11.1 vs 379.1±10.3 kcal; P<0.01), but the same percentage of calories provided
(85.7±1.8 vs 86.1±1.7 %kcal). Lean subjects rated hunger before breakfast the same on
both days (69.2±1.6 vs 71.7±1.4), as did the obese (69.8±1.6 vs 69.6±1.8), and there
was no difference between the groups. Lean subjects rated hunger after breakfast the
same on both days (27.8±1.9 vs 30.3±2.4), as did the obese (25.0±1.7 vs 24.3±1.8).
The reduction in hunger score following breakfast was significant for both groups
(P<0.0001), with the obese reporting significantly less hunger/more fullness after
breakfast than the lean (P=0.02). Fasting ghrelin was significantly greater in the lean
than obese women (549.9±58.9 vs 231.0±29.1 pg/ml; P<0.0001). Ghrelin was
significantly reduced at 60 min following breakfast in the lean (375.8±49.2 pg/ml;
P=0.028) but not the obese (212.2±26.4 pg/ml). Ghrelin was not related to hunger score
prior to breakfast, and there was no relationship between reduction in ghrelin and hunger
score in the lean or obese.
Conclusion: Caloric intake (as a percentage provided) and hunger scores before
breakfast on two occasions were the same for both lean and obese women. Fasting
ghrelin was significantly different between lean and obese women but did not predict
hunger score or calories consumed. Our findings do not support a role for ghrelin in
driving food intake at breakfast
