Exercise Training Reduces Reward for High-Fat Food in Adults With Overweight/Obesity

Kristine Beaulieu; Mark Hopkins; Catherine Gibbons; Pauline Oustric; Phillipa Caudwell; John Blundell; Grahamfinlayson

Disclosures

Med Sci Sports Exerc. 2020;52(4):900-908. 

In This Article

Results

Participant Characteristics

Participant characteristics at baseline and postintervention are described in Table 1. Baseline characteristics of exercisers and controls were similar (P > 0.13 for all). There were interactions between week and group for BMI, total mass, body fat percentage, fat mass, and waist circumference (all, P < 0.001, η2 p ≥ 0.19). The week–group interaction for fat-free mass was weaker (P = 0.22, η2 p = 0.03).

In exercisers, the training intervention led to reductions in BMI (M ΔPre–Post = −0.6 kg·m−2, P < 0.001, η2 p = 0.25; 95% CI, −0.9 to −0.3 kg·m−2), total mass (M ΔPre–Post = −1.8 kg, P < 0.001, η2 p = 0.27; 95% CI, −2.6 to −1.0 kg), body fat percentage (M ΔPre–Post = −1.9%, P < 0.001, η2 p = 0.42; 95% CI, −2.5 to −1.3%), fat mass (M ΔPre–Post = −2.2 kg, P < 0.001, η2 p = 0.37; 95% CI, −3.0 to −1.5 kg), and waist circumference (M ΔPre–Post = −3.7 cm, P < 0.001, η2 p = 0.57; 95% CI, −4.5 to −2.9 cm). There were also increases in fat-free mass (M ΔPre–Post = 0.4 kg, P = 0.01, η2 p = 0.10; 95% CI, 0.1 to 0.8 kg) and V̇O2max (M ΔPre–Post = 5.7 mL·kg−1·min−1, P < 0.001, η2 p = 0.43; 95% CI, 3.7 to 7.6 mL·kg−1·min−1; not measured in controls).

In controls, there were increases in BMI (M ΔPre–Post = 0.4 kg·m−2, P = 0.08, η2 p = 0.05; 95% CI, −0.1 to 0.9 kg·m−2), total mass (M ΔPre–Post = 1.3 kg, P = 0.06, η2 p = 0.06; 95% CI, −0.04 to 2.7 kg), body fat percentage (M ΔPre–Post = 0.8%, P = 0.15, η2 p = 0.04; 95% CI, −0.3% to 1.8%), fat mass (M ΔPre–Post = 1.3 kg, P = 0.06, η2 p = 0.06; 95% CI, −0.1 to 2.6 kg), and waist circumference (M ΔPre–Post = 2.1 cm, P = 0.005, η2 p = 0.12; 95% CI, 0.6 to 3.6 cm).

The 12-wk intervention produced a mean group (exercisers–controls) body weight difference of −3.1 kg (95% CI, −4.3 to −1.9 kg) and waist circumference difference of −5.8 cm (95% CI, −7.5 to −4.1 cm).

Food Reward. Completers data were available in 38 exercisers and 14 controls (with the outlier removed).

For liking scores, exercisers had a lower liking than did controls overall (M ΔEx–C = −6.0 mm, P = 0.15, η2 p = 0.04 (95% CI, −14.2 to 2.2 mm); ITT: M ΔEx–C = −7.6 mm, P = 0.06, η2 p = 0.06 (95% CI, −15.5 to 0.2 mm)). A week–group interaction was not apparent (P = 0.75, η2 p = 0.002; ITT: P = 0.87, η2 p = 0.00), and there were no changes from baseline to postintervention in both groups (M ΔPre–Post = −1.1 mm, P = 0.24, η2 p = 0.03 (95% CI, −3.0 to 0.79 mm); ITT: M ΔPre–Post = −1.3 mm, P = 0.15, η2 p = 0.04 (95% CI, −3.1 to 0.5 mm)). Figure 1A shows only the main effect of the intervention on liking within each group, for clarity.

Figure 1.

Liking (A) and wanting (B) for high-fat relative to low-fat foods in exercisers (n = 38) and controls (n = 14) at baseline (B) and postintervention (PI). For clarity, the overallmean ofHFAT andHCHOand pre–post lunch is presented. Individual values of food reward are represented by the points, and the descriptive statistics by boxplot with median. The figure illustrates both the effect of exercise on food reward (difference between the two boxplots) and the interindividual variability in the changes. Repeated-measures ANOVA was conducted with post hoc Bonferroni adjustments. *Exercisers baseline vs postintervention (completers: P = 0.03, η2 p = 0.09; ITT: P = 0.01, η2 p = 0.10). †Exercisers vs controls postintervention (completers: P = 0.07, η2 p = 0.06; ITT: P = 0.02, η2 p = 0.09).

On comparison across test meal conditions (main effect of HFAT vs HCHO), liking was greater in HFAT relative to HCHO (M ΔHF–HC = 1.9 mm, P = 0.06, η2 p = 0.07 (95% CI, −0.1 to 3.9 mm); ITT: M ΔHF–HC = 1.9 mm, P = 0.05, η2 p = 0.06 (95% CI, −0.02 to 3.7 mm)). The interaction effect between condition and state (P = 0.02, η2 p = 0.11; ITT: P = 0.04, η2 p = 0.07) showed minimal differences in liking between HFAT and HCHO in the hungry state (M ΔHF–HC = 0.3 mm, P = 0.81, η2 p = 0.001 (95% CI, −2.2 to 2.8 mm); ITT: M ΔHF–HC = 0.4 mm, P = 0.73, η2 p = 0.002 (95% CI, −2.1 to 2.9 mm)), but liking was greater in HFAT relative to HCHO in the fed state (M ΔHF–HC = 3.5 mm, P = 0.003, η2 p = 0.17 (95% CI, 1.3 to 5.7 mm); ITT: M ΔHF–HC = 3.3 mm, P = 0.003, η2 p = 0.14 (95% CI, 1.2 to 5.4 mm)). There were no other apparent effects or interactions.

For wanting scores, exercisers had lower wanting than did controls overall (M ΔEx–C = −11.1, P = 0.17, η2 p = 0.04 (95% CI, −27.2 to 4.9); ITT: M ΔEx–C = −15.4, P = 0.06, η2 p = 0.06 (95% CI, −31.3 to 0.5)). The week–group interaction effect (P = 0.08, η2 p = 0.06; ITT: P = 0.06, η2 p = 0.06) showed that exercisers reduced wanting from baseline to postintervention (M ΔPre–Post = −4.1, P = 0.03, η2 p = 0.09 (95% CI, −7.8 to −0.4); ITT: M ΔPre–Post = −4.4, P = 0.01, η2 p = 0.10 (95% CI, −7.7 to −1.0)) but not controls (M ΔPre–Post = 2.3, P = 0.45, η2 p = 0.01 (95% CI, −3.8 to 8.3); ITT: M ΔPre–Post = 2.3, P = 0.46, η2 p = 0.01 (95% CI, −3.8 to 8.4)). Exercisers also had lower wanting scores than did controls after intervention (M ΔEx–C = −14.3, P = 0.07, η2 p = 0.06 (95% CI, −30.0 to 1.4); ITT: M ΔEx–C = −18.7, P = 0.02, η2 p = 0.09 (95% CI, −34.4 to −3.1)). Figure 1B shows only the main effect of the intervention on wanting within each group, for clarity.

The week–state interaction effect (P = 0.04, η2 p = 0.08; ITT: P = 0.06, η2 p = 0.06), suggested reductions in wanting from hungry to fed postintervention (M ΔH–Fed = −5.3, P = 0.10, η2 p = 0.05 (95% CI, −11.7 to 1.0); ITT: M ΔH–Fed = −5.3, P = 0.08, η2 p = 0.05 (95% CI, −11.3 to 0.7) and from baseline to postintervention in the fed state (M ΔPre–Post = −3.3, P = 0.10, η2 p = 0.05 (95% CI, −7.2 to 0.6); ITT: M ΔPre–Post = −3.2, P = 0.10, η2 p = 0.05 (95% CI, −7.1 to 0.6)).

The main effect of condition showed that wanting was greater in HFAT relative to HCHO (M ΔHF–HC = 3.0, P = 0.03, η2 p = 0.09 (95% CI, 0.2 to 5.8); ITT: M ΔHF–HC = 2.9, P = 0.03, η2 p = 0.08 (95% CI, 0.3 to 5.4)). The interaction effect between condition, state, and group (P = 0.08, η2 p = 0.06; ITT: P = 0.09, η2 p = 0.05) suggested lower wanting in exercisers than in controls when hungry in HFAT (M ΔEx–C = −13.2, P = 0.11, η2 p = 0.05 (95% CI, −29.6 to 3.3); ITT: M ΔEx–C = −17.5, P = 0.04, η2 p = 0.07 (95% CI, −34.1 to −0.9)) and HCHO (M ΔEx–C = −13.7, P = 0.12, η2 p = 0.05 (95% CI, −31.2 to 3.8); ITT: M ΔEx–C = −17.7, P = 0.05, η2 p = 0.07 (95% CI, −35.2 to −0.1)), and when fed in HFAT (M ΔEx–C = −12.0, P = 0.17, η2 p = 0.04 (95% CI, −29.5 to 5.5); ITT: M ΔEx–C = −16.5, P = 0.06, η2 p = 0.06 (95% CI, −33.7 to 0.6)). Controls also had greater wanting after HFAT compared with HCHO in the fed state (M ΔHF–HC = 7.3, P = 0.01, η2 p = 0.12 (95% CI, 1.6 to 13.1); ITT: M ΔHF–HC = 7.3, P = 0.009, η2 p = 0.11 (95% CI, 1.9 to 12.8)). There were no other apparent effects or interactions.

Eating Behavior Traits. Completers' data were available for 46 exercisers (45 for binge eating) and 12 controls, and ITT for 14 controls. As shown in Table 2, baseline scores for exercisers and controls were similar (P > 0.15 for all).

For restraint, there were minimal differences from baseline to postintervention across groups (M ΔPre–Post = −0.5, P = 0.37, η2 p = 0.01 (95% CI, −1.5 to 0.6); ITT: M ΔPre–Post = −0.4, P = 0.38, η2 p = 0.01 (95% CI, −1.4 to 0.5)) and between groups (M ΔEx–C = −1.2, P = 0.32, η2 p = 0.02 (95% CI, −3.6 to 1.2); ITT: M ΔEx–C = −1.2, P = 0.31, η2 p = 0.02 (95% CI, −3.5 to 1.1)), and no apparent week–group interaction (P = 0.89, η2 p = 0.00; ITT: P = 0.94, η2 p = 0.00).

For disinhibition, there were minimal differences between groups (M ΔEx–C = −0.6, P = 0.60, η2 p = 0.005 (95% CI, −2.8 to 1.6; ITT: M ΔEx–C = −0.9, P = 0.40, η2 p = 0.01 (95% CI, −2.9 to 1.2). The interaction effect between week and group (P = 0.23, η2 p = 0.03; ITT: P = 0.20, η2 p = 0.03) suggested a decrease in disinhibition from baseline to postintervention in exercisers (M ΔPre–Post = −0.7, P = 0.02, η2 p = 0.10 (95% CI, −1.3 to −0.1); ITT: M ΔPre–Post = −0.7, P = 0.01, η2 p = 0.10 (95% CI, −1.2 to −0.1)) but not in controls (M ΔPre–Post = 0.04, P = 0.94, η2 p = 0.0 (95% CI, −1.1 to 1.1); ITT: M ΔPre–Post = 0.04, P = 0.94, η2 p = 0.0 (95% CI, −1.0 to 1.0)).

For susceptibility to hunger, exercisers had lower scores than did controls overall (M ΔEx–C = −1.5, P = 0.18, η2 p = 0.03 (95% CI, −3.7 to 0.7); ITT: M ΔEx–C = −1.9, P = 0.07, η2 p = 0.06 (95% CI, −4.0 to 0.1)). The week–group interaction (P = 0.33, η2 p = 0.02; ITT: P = 0.35, η2 p = 0.02) suggested that exercisers had lower scores than did controls postintervention (M ΔEx–C = −1.9, P = 0.11, η2 p = 0.04 (95% CI, −4.2 to 0.5; ITT: M ΔEx–C = −2.2, P = 0.04, η2 p = 0.07 (95% CI, −4.4 to −0.01).

For binge eating score, differences between groups were minimal (M ΔEx–C = −1.8, P = 0.46, η2 p = 0.01 (95% CI, −6.4 to 2.9; ITT: M ΔEx–C = −2.5, P = 0.25, η2 p = 0.02 (95% CI, −6.9 to 1.8). The interaction between week and group (P = 0.06, η2 p = 0.06; ITT: P = 0.06, η2 p = 0.06) revealed a decrease in exercisers (M ΔPre–Post = −1.5, P = 0.01, η2 p = 0.11 (95% CI, −2.7 to −0.4); ITT: M ΔPre–Post = −1.5, P = 0.01, η2 p = 0.11 (95% CI, −2.6 to −0.4)) but not in controls (M ΔPre–Post = 0.9, P = 0.44, η2 p = 0.01 (95% CI, −1.4 to 3.1); ITT: M ΔPre–Post = 0.8, P = 0.46, η2 p = 0.009 (95% CI, −1.3 to 2.8)).

Relationship Between Changes in Food Reward, Eating Behavior Traits, and Body Weight and Composition. In the whole sample and in controls, changes in wanting scores were weakly associated with changes in binge eating, and weakened further in exercisers alone (Tables, Supplemental Digital Content 3, Pearson correlation matrix of the associations among changes in food reward, eating behavior traits and body composition in the whole group, http://links.lww.com/MSS/B828; Supplemental Digital Content 4, Pearson correlation matrix of the associations among changes in food reward, eating behavior traits, and body composition in exercisers, http://links.lww.com/MSS/B829; Supplemental Digital Content 5, Pearson correlation matrix of the associations among changes in food reward, eating behavior traits, and body composition in controls, http://links.lww.com/MSS/B830). In the whole sample, changes in body weight, fat mass, and, more weakly, body fat percentage were associated with changes in eating behavior traits but not with changes in food reward. These associations were weaker in the exercisers alone and not apparent in the controls alone, except for disinhibition.

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