Weight Loss, but Not Dairy Composition of Diet, Moderately Affects Satiety and Postprandial Gut Hormone Patterns in Adults

Abstract

Background: Inclusion of dairy in diet patterns has been shown to have mixed effects on weight loss. A prevailing hypothesis is that dairy improves weight loss by influencing endocrine systems associated with satiety and food intake regulation.

Objectives: The objective of the current study was to evaluate the effect of weight loss with or without adequate dietary dairy on subjective and objective appetitive measures.

Methods: Men and women who were habitual low dairy consumers (n = 65, 20-50 y) participated in a 12-wk randomized controlled feeding weight loss trial. During the 12-wk intervention, a low-dairy (<1 serving dairy/d) was compared with an adequate-dairy (3-4 servings dairy/d) diet, both with a 500-kcal deficit/d. Test days, before and at the end of the intervention, began with 2 fasting blood draws and visual analog scale (VAS) measures, followed by a standard breakfast (25% of prescribed restricted calories), 5 postbreakfast blood draws and VASs, a standard lunch (40% of restricted energy amount), and 12 postlunch blood draws and VASs. Blood samples were used for satiety hormone measurements. On a separate day when matching standard meals were consumed, an ad libitum buffet meal was provided as dinner, at a self-selected time. Meal duration and intermeal interval were recorded.

Results: Weight loss (-6.1 kg), irrespective of dairy, resulted in reduced fasting insulin (-20%) and leptin (-25%), and increased fasting acylated ghrelin (+25%) and VAS desire to eat (+18%) (P < 0.05). There were no effects of dairy on objective or subjective satiety measures. Weight loss marginally reduced the intermeal interval (289 min compared with 276 min, P = 0.059) between lunch and the ad libitum buffet.

Conclusions: These results do not support the hypothesis that inclusion of dairy in long-term dietary patterns influences appetite during weight loss. Weight loss per se has a modest impact on select systems that regulate hunger and satiety.This trial was registered at clinicaltrials.gov as NCT00858312.

Keywords: ad libitum buffet; appetite; dairy; desire to eat; ghrelin; leptin; satiety; weight loss.

Published by Oxford University Press on behalf of the American Society for Nutrition 2020.

Figures

FIGURE 1

Study design overview. Participants had a 3-wk LD energy balance run-in diet, followed by 12 wk of a 500-kcal-deficit/d intervention diet randomly assigned to either an LD group or an AD group. TDEE was based on a prescribed 500-kcal-deficit diet. Relative to the lunch meal at 0 min, blood draws were done at −295 and −285 min for fasting; −240, −200, −140, −80, and −25 min for postbreakfast measures; and 5, 20, 40, 60, 90, 120, 150, 180, 210, 240, 270, and 300 min for postlunch measures. *The buffet meal challenge test day was on a separate test day than the endocrine measures. AD, adequate dairy; LD, low dairy; TDEE, total daily energy expenditure; VAS, visual analog scale.

FIGURE 2

AUCs for ghrelin (A), insulin (B), and visual analog scale hunger score (C) of adult female and male study volunteers before and after a ∼12-wk weight loss intervention that showed differences as a result of the intervention, measured 5 times between breakfast and lunch (postbreakfast) and 12 times after lunch (postlunch). All data are means ± SEMs, n = 34 (LD) or n = 31 (AD). Relative to the lunch meal at 0 min, blood draws were done at −295 and −285 min for fasting; −240, −200, −140, −80, and −25 min for postbreakfast measures; and 5, 20, 40, 60, 90, 120, 150, 180, 210, 240, 270, and 300 min for postlunch measures. Labeled means without a common letter differ by weeks or by treatment group, P < 0.05. For ghrelin, note that postprandial concentrations dropped; the AUC represents the magnitude of the reductions. AD, adequate dairy; BL, baseline; LD, low dairy; PI, postintervention.

FIGURE 3

Buffet parameters irrespective of dairy intervention group of adult female and male study volunteers before and after a ∼12-wk weight loss intervention. (A) Intermeal interval, (B) energy intake, (C) percentage of prescribed daily energy consumed, and (D) total fat, (E) total carbohydrate, and (F) total protein intakes. All data are means ± SEMs, n = 34 (low dairy) or n = 31 (adequate dairy). *PI tended to differ from BL, P = 0.06. Percentage of daily prescribed energy consumed indicates the percentage of prescribed treatment energy (500-kcal restriction) consumed during the buffet. BL, baseline; PI, postintervention.