Elsevier

Physiology & Behavior

Volume 96, Issue 2, 16 February 2009, Pages 270-275
Physiology & Behavior

Decelerated and linear eaters: Effect of eating rate on food intake and satiety

https://doi.org/10.1016/j.physbeh.2008.10.011Get rights and content

Abstract

Women were divided into those eating at a decelerated or linear rate. Eating rate was then experimentally increased or decreased by asking the women to adapt their rate of eating to curves presented on a computer screen and the effect on food intake and satiety was studied. Decelerated eaters were unable to eat at an increased rate, but ate the same amount of food when eating at a decreased rate as during the control condition. Linear eaters ate more food when eating at an increased rate, but less food when eating at a decreased rate. Decelerated eaters estimated their level of satiety lower when eating at an increased rate but similar to the control condition when eating at a decreased rate. Linear eaters estimated their level of satiety similar to the control level despite eating more food at an increased rate and higher despite eating less food at a decreased rate. The cumulative satiety curve was fitted to a sigmoid curve both in decelerated and linear eater under all conditions. Linear eaters rated their desire to eat and estimated their prospective intake lower than decelerated eaters and scored higher on a scale for restrained eating. It is suggested that linear eaters have difficulty maintaining their intake when eating rate is dissociated from its baseline level and that this puts them at risk of developing disordered eating. It is also suggested that feedback on eating rate can be used as an intervention to treat eating disorders.

Introduction

Kissileff described a method for continuous recording of food intake in man, the Universal Eating Monitor [1]. The subject places a plate on a scale and puts food on the plate and a computer records the weight loss of the plate during the meal. Using this procedure and careful mathematical modeling, the cumulative food intake of normal volunteers was fitted to a quadratic equation and the curve had a decelerated shape in most subjects [2], [3]. A review of the research performed with this method [4] showed that restrained eating, which is thought of as a self-imposed cognitive strategy to restrict food intake in order to control body weight [5], [6] is an important factor that affects eating behavior. Restrained eaters eat at a constant rate compared to unrestrained eaters, who eat at a decelerated rate [7]. A visual analogue scale for rating of satiety was subsequently added to this procedure and it was suggested that satiety is relatively constant in the beginning of the meal and then increases in a linear fashion in restrained eaters and that satiety displays a similar curve that levels off by the end of the meal in unrestrained eaters [4], [8], [9].

We have further developed these methods for different purposes by adding a touch screen. Curves for eating rate are displayed on the touch screen to provide visual feedback during meals and the participants are asked to follow these curves when they eat. This is possible because the subject can see her/his eating rate appearing on the screen during the meal. Thus, this method, Mandometer®, makes it possible to increase or decrease eating rate experimentally. We also display a scale on the touch screen and ask participants to rate how full they feel. Thus, Mandometer® also yields an estimate of the development of satiety.

In the present study, we examined the effect of experimental manipulation of eating rate on food intake and the development of satiety in women who were first divided into those eating at a decelerated or linear rate. Specifically, we wanted to know if women with a decelerated pattern of eating respond differently to changes in the rate of eating than women with a linear pattern of eating. In other words, the aim of this study was to evaluate the role of individual eating patterns on food intake and satiety when the rate of eating diverts from the subject's habituated rate. Previous research has suggested that changes in eating rate affect food intake [reviewed in Ref. [10]].

Section snippets

Subjects

Forty-seven normal-weight (body mass index, BMI = 22.2 (20.2–24.3) kg/m2) (median; range) women (aged 21.2 (19.5–23.1) years) were recruited by advertisement on a nearby college campus. They completed a health questionnaire to ensure that they met the criteria for inclusion in the study. They should be 18–25 years old and have a normal BMI = 19–25 kg/m2. They should be healthy, non-smokers, free from food allergies and they should not have a history of eating disorders or use medication known to

Decelerated and linear eaters

Two different patterns of eating were identified in the baseline test (Fig. 1). Thus, in 17 women the cumulative curve of food intake was decelerated (a <  1) and in the 30 other women the curve was linear (a  0). There was no overlap in the a-values between the two groups [t(45) =  14.42, p < 0.001]. The women are, therefore, referred to as decelerated and linear eaters in the following.

Decelerated eaters ate at an initially higher rate than linear eaters [t(45) = 8.60, p < 0.001], (Fig. 1), but the

Discussion

The data on cumulative food intake in the women in this study fitted a quadratic curve as described before [2], [3]. This pattern is very stable from test to test [present data, [3], [4], [16], [17]]. However, while a “quadratic curve adequately describes the cumulative food intake in man” [2], [3], it obviously does not predict intake beyond the duration of the meal; a positive quadratic term indicates that intake escalates over time and a negative term indicates that intake declines over

Acknowledgement

This work was supported by AB Mando.

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