5 research outputs found
Ghrelin is not Related to Hunger or Calories Consumed at Breakfast in Lean and Obese Women
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
The Effect of a Diet Containing 70% Protein from Plants on Mineral Metabolism and Musculoskeletal Health in Chronic Kidney Disease
Ventral frontal satiation-mediated responses to food aromas in obese and normal-weight women
BACKGROUND:
Sensory properties of foods promote and guide consumption in hunger states, whereas satiation should dampen the sensory activation of ingestive behaviors. Such activation may be disordered in obese individuals.
OBJECTIVE:
Using functional magnetic resonance imaging (fMRI), we studied regional brain responses to food odor stimulation in the sated state in obese and normal-weight individuals targeting ventral frontal regions known to be involved in coding for stimulus reward value.
DESIGN:
Forty-eight women (25 normal weight; 23 obese) participated in a 2-day (fed compared with fasting) fMRI study while smelling odors of 2 foods and an inedible, nonfood object. Analyses were conducted to permit an examination of both general and sensory-specific satiation (satiation effects specific to a given food).
RESULTS:
Normal-weight subjects showed significant blood oxygen level-dependent responses in the ventromedial prefrontal cortex (vmPFC) to food aromas compared with responses induced by the odor of an inedible object. Normal-weight subjects also showed general (but not sensory-specific) satiation effects in both the vmPFC and orbitofrontal cortex. Obese subjects showed no differential response to the aromas of food and the inedible object when fasting. Within- and between-group differences in satiation were driven largely by changes in the response to the odor of the inedible stimulus. Responses to food aromas in the obese correlated with trait negative urgency, the tendency toward negative affect-provoked impulsivity.
CONCLUSIONS:
Ventral frontal signaling of reward value may be disordered in obesity, with negative urgency heightening responses to food aromas. The observed nature of responses to food and nonfood stimuli suggests that future research should independently quantify each to fully understand brain reward signaling in obesity