Eating Rate Affects Binge Size in Controls but Not Bulimia Patients
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This study investigated the effects of eating rate on binge size in patients with bulimia nervosa (BN) and control subjects. In a controlled experiment, all subjects consumed an unlimited calorie shake at either a slow (70g/min) or fast (140g/min) rate. While controls ate significantly more during the fast rate, eating rate did not affect intake in BN patients. The results suggest that BN patients lack the normal physiological mechanisms that modulate meal size based on eating rate. Determining whether this differs for normal eating or in obese individuals requires further research.
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Eating Rate Affects Binge Size in Controls but Not Bulimia Patients
- 1. Effects of Eating Rate on Binge Size in Bulimia Nervosa JL Guss, HR Kissileff, M Torres, H Lofink, MJ Devlin, E Zimmerli, BT Walsh July 13, 2005 Obesity Research Center St. Luke’s/Roosevelt Hospital-Columbia University
- 2. Background: Bulimia Nervosa (BN) 3 BN is an eating disorder characterized by episodes of excess food intake (i.e. binges). 3 Patientseat faster than do normal subjects, but only in binge meals.
- 3. Cumulative Intake Curves in Binges 1800 1600 1400 1200 Intake (g) 1000 800 600 400 Patients 200 Controls 0 0 2 4 6 8 10 12 14 16 18 20 Time (min) – BN patients eat faster and fail to decelerate
- 4. Eating Rate: Related to Intake & Fullness 3 We found that rates of eating rate correlate… - Positively with amount eaten in a binge, and… - Negatively with fullness development in a binge
- 5. Meal Size Increases with Eating Rate 2200 2000 B Patients B B C Controls 1800 C B 1600 B B 1400 Intake (g) C B 1200 C 1000 C C C 800 C C C B B B B C 600 400 C C 200 0 50 100 150 200 250 Rate of Eating (g/min)
- 6. Increasing Fullness Lessens with Eating Rate 0.6 Rate of Fullness Increase (mm/g) 0.5 C BB 0.4 B B B B 0.3 0.2 C C B C B 0.1 C C B C B BB B B C B B C B BC B 0.0 C B CC B C C -0.1 0 20 40 60 80 100 120 140 160 Eating Rate (g/min)
- 7. Background: Studies of Rate & Intake 3 No studies have directly manipulated rate of intake to determine its effect on binge size. 3 Treatment programs aiming to reduce consumption, including those for BN and obesity, emphasize reducing one's eating rate, but the effect of such behavioral modification have never been subjected to experimental manipulation.
- 8. Study Aim 3 To test the hypothesis that binge size is mediated, in part, by rate of eating. 3 To determine the effect of eating rate on binge size.
- 9. 2x2 Mixed-Model Design G ro u p : P a t ie n t / C o n t r o l S cre e n M e a l S lo w R a t e F a s t R a te 7 0 g / m in 1 4 0 g / m in 3 Group: between-subjects factor 3 Rate: within-subjects, counterbalanced factor
- 10. Procedure 3 6h prior to meal, subjects ate a 300 kcal breakfast 3 At meal subjects were told: let yourself go & binge eat 3 Subject kept shake between lines on cup that filled by a pump to pace subjects at designated rate: – Fast: 140 g/min - Slow: 70 g/min 3 Fast rate based on patients' previous eating rates and in order to be tolerable to controls but fast enough to see differences from slow rate 3 The test meal was a strawberry yogurt shake
- 11. Test Meal: Strawberry Yogurt Shake 3 Energy Density: 1.04 kcal/g q 12.5% protein q 67.4% carbohydrate q 20.2% fat 3 Unlimited quantity available
- 12. Food Pump: kept subjects' intake at filling rate
- 13. Universal Eating Monitor: continuously weighs food
- 14. Subjects 3 Women with and without BN recruited from NYC area 3 BN patients met DSM-IV criteria, diagnosed via SCID Controls Patients n 16 15 Age (yrs) 24.7 2 0.9 26.3 2 1.2 Weight (lbs) 127 1 3.2 125 1 4.2 Height (in) 64.5 6 0.6 63.7 6 0.8 BMI (kg/m2) 21.5 2 0.4 21.9 2 0.5
- 15. Results 3 Patients ate significantly more than controls in meals at both slow and fast rate: q BN's ate 363g more than controls during fast rate q BN's ate 480g more than controls during slow rate 3 Controls ate 182 g (± 81.7) more during the fast vs slow rate (p=0.03). 3 Patients ate 65 g (± 84.4) more during the fast vs slow rate (NS). 3 There was no order effect.
- 16. Effect of Eating Rate on Binge Size 1400 Patients Controls 1200 1000 Intake (g) 800 600 400 Slow Fast Rate (g/min)
- 17. Control Subjects 2200 ROE01b ROE02 2000 ROE03 ROE04 1800 ROE05 ROE06a 1600 ROE07a ROE08 1400 ROE09 Intake (g) ROE10 ROE11 1200 ROE12 ROE13 1000 ROE14 ROE15 800 ROE16 Mean 600 400 200 Slow Fast Rate
- 18. BN Patients 2200 2000 ROE17a ROE18 ROE19 1800 ROE20 ROE21 1600 ROE22b ROE23 1400 Intake (g) ROE24 ROE25 1200 ROE26 ROE27a 1000 ROE28 ROE29 800 ROE30 ROE32 600 Mean 400 200 Slow Rate Fast
- 19. Summary & Conclusion 3 The fast eating rate significantly increased intake in controls, but had no effect in patients with BN. 3 Results suggest that eating rate modulates meal size in normal individuals, but patients either lack such modulation or ignore the physiologic signals upon which such modulation acts. 3 Future studies must address whether… q This effect differs if subjects eat normally-not binge q The obese are more similar to patients or controls
- 20. Control Subjects 2200 ROE01b ROE02 2000 ROE03 ROE04 1800 ROE05 ROE06a 1600 ROE07a ROE08 1400 ROE09 Intake (g) ROE10 ROE11 1200 ROE12 ROE13 1000 ROE14 ROE15 800 ROE16 Mean 600 400 200 Slow Fast Rate
- 21. BN Patients 2200 2000 ROE17a ROE18 ROE19 1800 ROE20 ROE21 1600 ROE22b ROE23 Intake (g) 1400 ROE24 ROE25 1200 ROE26 ROE27a 1000 ROE28 ROE29 800 ROE30 ROE32 600 Mean 400 200 Slow Rate Fast
- 22. Effect of Eating Rate on Binge Size 1400 Patients Controls 1200 1000 Intake (g) 800 600 400 Slow Fast Rate (g/min)
Editor's Notes
- Need to add units Gerry – divide in half – would get different relation Bart – does chocolate condition satiety better than something else Janet – not food itself – it could but no evidence for it Foltin – take out outlier Scwartz –rate goes back to preload and multi item meals – multiple delays after fixed preloads – post oral processing deficit – what is rate under long delay – if satiety deficit would maintain more rapid – Smith – real deficit is in mouth – Asks Foltin – any kind of late divergence in drug data – after meds increase in interval between presses slows down – How does manipulation change – eg. Blundell fenflor doesn’t affect initial argues for satiety – benzodiazopenes – monkeys straight up Smith what if reward sustains behavior and put on interval schedule – Foltin progressive ratio vs fixed with big interval - work for chocolate – interaction between sched and reinf - interval between reinf – if fixed ratio with long interval stop – time interval is critical. Gibbs – have to eat fast to prevent stopping signals Bart – like behavior mod Tim where to go what hypoth? Gerry if sham feeding - do with and without imposed interval Gary unopposed vs interuption Gerry – imposing intervals allows post ingestive to get stronger – Gary rate and intake constant up to 450 – if post oral longer wait, stronger the signal- give 450 preload and wait 5 10 etc delays – is there a diff between patients and controls Janet – if eating faster effect mediated by oral ?? Gerry – closer the preload more effective
- Added real data Tim worried about variability – Gibbs – what about homogeneity of group – single or multi item binges Schwartz – At end of this give them another meal? We haven’t done it.