Experimental psychologist working in the broad field of behavioural nutrition, with interests and expertise in flavour perception, learned food preferences, human appetite control and effects of food and drink ingredients on mood and cognition. Address: United Kingdom
A high carbohydrate/low fat diet is recommended for reduced risk of overeating, but it is not cle... more A high carbohydrate/low fat diet is recommended for reduced risk of overeating, but it is not clear whether satiety responses to carbohydrate and fat differ between individuals. The objective of this study was to determine how women with either a low or a high tendency to overeat (TFEQ-disinhibition) and with either a low or a high tendency to restrict intake (TFEQ-restraint) respond to fat and carbohydrate consumed at breakfast. Sixty-four healthy-weight women preselected for high and low TFEQ scores of restraint and disinhibition were enrolled for the study. They came to the laboratory on two separate days to consume breakfast; on one day the principle energy source was fat and on the other day carbohydrate. Satiety responses were determined by ratings of hunger and fullness for 2 h after breakfast, and intake at a mid-morning snack test. Those scoring high on the TFEQ-disinhibition scale consumed more energy at the snack test than those with low TFEQ-disinhibition, but this was only following the high carbohydrate breakfast. The TFEQ-restraint scale did not independently predict food intake or interact with the TFEQ-disinhibition related overeating. In normal-weight females the tendency to overeat may be related to insensitivity to the satiating effects of carbohydrate.
Attempts to induce overeating through mood or stress manipulations in restrained eaters have had ... more Attempts to induce overeating through mood or stress manipulations in restrained eaters have had mixed success. A previous study in our laboratory suggested that overeating induced by stress was only evident at lunchtime for women who scored high on both the Three Factor Eating Questionnaire (TFEQ) Restraint and Disinhibition scales. Here we extend those findings to examine the effects of induced positive and negative mood on snacking by women classified similarly. Women (n=96) were provided with snack foods to sample while watching a neutral, positive or negative film. Those scoring high on both TFEQ measures ate most in the Negative affect condition, whereas those who scored low in restraint but high in disinhibition ate most in the Positive affect condition, and least in the negative condition. Women who scored low on the disinhibition measure ate similar amounts in all three film conditions regardless of restraint. Mood data confirmed that both negative and Positive affect films were equally arousing, but their emotional valence determined effects on eating. Thus arousal alone was not an adequate explanation for mood-induced eating. These data suggest that restraint alone is a poor predictor of likelihood of overeating in response to stress, which may explain discrepancies in the existing stress-eating literature, and also suggest that positive mood enhances the tendency to overeat in the absence of restraint.
Page 76. 4 Appetite and Food Intake: A Human Experimental Perspective Martin R. Yeomans and Emma ... more Page 76. 4 Appetite and Food Intake: A Human Experimental Perspective Martin R. Yeomans and Emma J. Bertenshaw contents 4.1. Introduction..... 61 4.2. Defining. Appetite..... ...
Previous studies have shown that caffeine can reinforce flavour liking in overnight deprived mode... more Previous studies have shown that caffeine can reinforce flavour liking in overnight deprived moderate caffeine consumers (e.g. average of 250 mg/day) but not in low consumers (<120 mg/day). However, it is not possible to determine whether the difference between moderate and low caffeine consumers results from pre-existing individual differences in response to caffeine, or results directly from the different amounts of caffeine they habitually consume. If the former were true, then moderate consumers who are completely withdrawn should still manifest the flavour conditioning effect. Conversely, if the latter were true, consumers who are completely withdrawn should not manifest the effect. To examine whether moderate caffeine consumers who have been fully withdrawn from caffeine manifest the flavour conditioning effect. In a double-blind study, 48 moderate caffeine consumers refrained from consuming caffeine for 4 weeks and were given replacement drinks to consume, which were eithe...
Fowls were given intravenous (IV) injections of hypertonic solutions of NaCl, and subsequent wate... more Fowls were given intravenous (IV) injections of hypertonic solutions of NaCl, and subsequent water intakes were recorded. All concentrations of hypertonic NaCl increased drinking in the 90 min after injection, compared with control treatments. Increments in drinking in this time agreed closely with calculated amounts required to restore normal osmolality. In further experiments, delaying access to water by periods of 60-360 min after injection failed to reduce drinking elicited by hypertonic NaCl. Injections of 2.0 M NaCl caused increases in plasma osmolality and sodium concentration which were maintained throughout 360 min water deprivation, and caused prolonged reductions in hematocrit and plasma protein concentrations. These results demonstrate that cellular dehydration is a potent thirst stimulus in fowls, and imply that fowls do not reduce hyperosmolality by excretion of salt when water is unavailable.
Fowls were deprived of water for 2 or 6 hr, and then given graded intravenous (IV) injections of ... more Fowls were deprived of water for 2 or 6 hr, and then given graded intravenous (IV) injections of water or isotonic saline. With both levels of deprivation, water preloads caused dose-dependent reductions in water intake which matched closely the volumes of preload given, whereas isotonic saline preloads had no effect on drinking, and feeding was unaffected in both cases. These results imply that drinking elicited by short periods of water deprivation is a response to increased plasma osmolality rather than to a loss of extracellular fluid volume. In further experiments, water intakes were reduced by at least as much as the volume administered when undeprived fowls were given 6 hr continuous IV infusions or IV injections of water, and food intakes were also suppressed. Plasma analyses taken at the end of continuous infusions of water indicated a fall in osmolality during this time. It was concluded that whereas increases in plasma osmolality increase drinking in fowls, a fall in osmo...
Monosodium glutamate (MSG) has been shown to increase satiety when combined with protein. Inosine... more Monosodium glutamate (MSG) has been shown to increase satiety when combined with protein. Inosine 5&amp;amp;amp;amp;#39;-monophosphate acts synergistically with MSG when tasted, is present in high-protein sources, and may potentially further enhance satiety. We assessed effects of a combination of monosodium glutamate and inosine 5&amp;amp;amp;amp;#39;-monophosphate (MSG/IMP) provided either alone or in a high-energy, high-carbohydrate and -protein soup on appetite during ingestion and postingestive satiety. Fixed portions (450 g) of a low-energy control and high-energy, high-carbohydrate and -protein soup preload with added monosodium glutamate and inosine 5&amp;amp;amp;amp;#39;-monophosphate (MSG/IMP+) or without added monosodium glutamate and inosine 5&amp;amp;amp;amp;#39;-monophosphate (MSG/IMP-) were consumed on 4 nonconsecutive days, and changes in appetite during soup intake and at a subsequent ad libitum lunch were assessed in 26 low-restraint volunteers by using a within-participant design. MSG/IMP+ conditions significantly reduced subsequent intake more than the MSG/IMP- condition did irrespective of energy. The high-carbohydrate and -protein condition also reduced intake independently of MSG/IMP. Energy compensation was greater in the MSG/IMP+ carbohydrate and protein conditions than MSG/IMP- condition. The addition of the MSG/IMP+ also increased the soup pleasantness and caused an immediate increase in appetite when the soup was first tasted. The addition of MSG/IMP to a low-energy preload had a biphasic effect on appetite by stimulating appetite during ingestion and enhancing postingestive satiety. This trial was registered at www.controlled-trials.com/isrctn as ISRCTN14567895.
A high carbohydrate/low fat diet is recommended for reduced risk of overeating, but it is not cle... more A high carbohydrate/low fat diet is recommended for reduced risk of overeating, but it is not clear whether satiety responses to carbohydrate and fat differ between individuals. The objective of this study was to determine how women with either a low or a high tendency to overeat (TFEQ-disinhibition) and with either a low or a high tendency to restrict intake (TFEQ-restraint) respond to fat and carbohydrate consumed at breakfast. Sixty-four healthy-weight women preselected for high and low TFEQ scores of restraint and disinhibition were enrolled for the study. They came to the laboratory on two separate days to consume breakfast; on one day the principle energy source was fat and on the other day carbohydrate. Satiety responses were determined by ratings of hunger and fullness for 2 h after breakfast, and intake at a mid-morning snack test. Those scoring high on the TFEQ-disinhibition scale consumed more energy at the snack test than those with low TFEQ-disinhibition, but this was only following the high carbohydrate breakfast. The TFEQ-restraint scale did not independently predict food intake or interact with the TFEQ-disinhibition related overeating. In normal-weight females the tendency to overeat may be related to insensitivity to the satiating effects of carbohydrate.
Attempts to induce overeating through mood or stress manipulations in restrained eaters have had ... more Attempts to induce overeating through mood or stress manipulations in restrained eaters have had mixed success. A previous study in our laboratory suggested that overeating induced by stress was only evident at lunchtime for women who scored high on both the Three Factor Eating Questionnaire (TFEQ) Restraint and Disinhibition scales. Here we extend those findings to examine the effects of induced positive and negative mood on snacking by women classified similarly. Women (n=96) were provided with snack foods to sample while watching a neutral, positive or negative film. Those scoring high on both TFEQ measures ate most in the Negative affect condition, whereas those who scored low in restraint but high in disinhibition ate most in the Positive affect condition, and least in the negative condition. Women who scored low on the disinhibition measure ate similar amounts in all three film conditions regardless of restraint. Mood data confirmed that both negative and Positive affect films were equally arousing, but their emotional valence determined effects on eating. Thus arousal alone was not an adequate explanation for mood-induced eating. These data suggest that restraint alone is a poor predictor of likelihood of overeating in response to stress, which may explain discrepancies in the existing stress-eating literature, and also suggest that positive mood enhances the tendency to overeat in the absence of restraint.
Page 76. 4 Appetite and Food Intake: A Human Experimental Perspective Martin R. Yeomans and Emma ... more Page 76. 4 Appetite and Food Intake: A Human Experimental Perspective Martin R. Yeomans and Emma J. Bertenshaw contents 4.1. Introduction..... 61 4.2. Defining. Appetite..... ...
Previous studies have shown that caffeine can reinforce flavour liking in overnight deprived mode... more Previous studies have shown that caffeine can reinforce flavour liking in overnight deprived moderate caffeine consumers (e.g. average of 250 mg/day) but not in low consumers (<120 mg/day). However, it is not possible to determine whether the difference between moderate and low caffeine consumers results from pre-existing individual differences in response to caffeine, or results directly from the different amounts of caffeine they habitually consume. If the former were true, then moderate consumers who are completely withdrawn should still manifest the flavour conditioning effect. Conversely, if the latter were true, consumers who are completely withdrawn should not manifest the effect. To examine whether moderate caffeine consumers who have been fully withdrawn from caffeine manifest the flavour conditioning effect. In a double-blind study, 48 moderate caffeine consumers refrained from consuming caffeine for 4 weeks and were given replacement drinks to consume, which were eithe...
Fowls were given intravenous (IV) injections of hypertonic solutions of NaCl, and subsequent wate... more Fowls were given intravenous (IV) injections of hypertonic solutions of NaCl, and subsequent water intakes were recorded. All concentrations of hypertonic NaCl increased drinking in the 90 min after injection, compared with control treatments. Increments in drinking in this time agreed closely with calculated amounts required to restore normal osmolality. In further experiments, delaying access to water by periods of 60-360 min after injection failed to reduce drinking elicited by hypertonic NaCl. Injections of 2.0 M NaCl caused increases in plasma osmolality and sodium concentration which were maintained throughout 360 min water deprivation, and caused prolonged reductions in hematocrit and plasma protein concentrations. These results demonstrate that cellular dehydration is a potent thirst stimulus in fowls, and imply that fowls do not reduce hyperosmolality by excretion of salt when water is unavailable.
Fowls were deprived of water for 2 or 6 hr, and then given graded intravenous (IV) injections of ... more Fowls were deprived of water for 2 or 6 hr, and then given graded intravenous (IV) injections of water or isotonic saline. With both levels of deprivation, water preloads caused dose-dependent reductions in water intake which matched closely the volumes of preload given, whereas isotonic saline preloads had no effect on drinking, and feeding was unaffected in both cases. These results imply that drinking elicited by short periods of water deprivation is a response to increased plasma osmolality rather than to a loss of extracellular fluid volume. In further experiments, water intakes were reduced by at least as much as the volume administered when undeprived fowls were given 6 hr continuous IV infusions or IV injections of water, and food intakes were also suppressed. Plasma analyses taken at the end of continuous infusions of water indicated a fall in osmolality during this time. It was concluded that whereas increases in plasma osmolality increase drinking in fowls, a fall in osmo...
Monosodium glutamate (MSG) has been shown to increase satiety when combined with protein. Inosine... more Monosodium glutamate (MSG) has been shown to increase satiety when combined with protein. Inosine 5&amp;amp;amp;amp;#39;-monophosphate acts synergistically with MSG when tasted, is present in high-protein sources, and may potentially further enhance satiety. We assessed effects of a combination of monosodium glutamate and inosine 5&amp;amp;amp;amp;#39;-monophosphate (MSG/IMP) provided either alone or in a high-energy, high-carbohydrate and -protein soup on appetite during ingestion and postingestive satiety. Fixed portions (450 g) of a low-energy control and high-energy, high-carbohydrate and -protein soup preload with added monosodium glutamate and inosine 5&amp;amp;amp;amp;#39;-monophosphate (MSG/IMP+) or without added monosodium glutamate and inosine 5&amp;amp;amp;amp;#39;-monophosphate (MSG/IMP-) were consumed on 4 nonconsecutive days, and changes in appetite during soup intake and at a subsequent ad libitum lunch were assessed in 26 low-restraint volunteers by using a within-participant design. MSG/IMP+ conditions significantly reduced subsequent intake more than the MSG/IMP- condition did irrespective of energy. The high-carbohydrate and -protein condition also reduced intake independently of MSG/IMP. Energy compensation was greater in the MSG/IMP+ carbohydrate and protein conditions than MSG/IMP- condition. The addition of the MSG/IMP+ also increased the soup pleasantness and caused an immediate increase in appetite when the soup was first tasted. The addition of MSG/IMP to a low-energy preload had a biphasic effect on appetite by stimulating appetite during ingestion and enhancing postingestive satiety. This trial was registered at www.controlled-trials.com/isrctn as ISRCTN14567895.
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