ORCID Profile
0000-0003-0534-3072
Current Organisation
University of Melbourne
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Publisher: Elsevier BV
Date: 12-2023
Publisher: Elsevier BV
Date: 02-1998
DOI: 10.1016/S0031-9384(97)00517-9
Abstract: The effects of gastric infusions of fat and carbohydrate on physiological and psychological measures were compared using a within subject design in 9 healthy subjects (6 males). Each subject received isovolaemic rapid gastric infusions of sucrose solution (100% energy carbohydrate), lipid emulsion (100% energy fat, 20% Intralipid), and a non-nutrient control (0.9% saline) in a randomised order. Nutrient infusions were isoenergetic, containing one-third of an in idual subject's estimated daily energy requirements (mean, 3227 kJ range, 2479-3971 kJ). Measures of heart rate (HR), energy expenditure (EE), mood, and sleepiness were collected before the infusions and every 0.5 h for 3.5 h. Mean postingestive HR, EE, and satiation were significantly greater after the nutrient infusions than after the control. Sucrose induced a rapid increase in HR and EE, whereas lipid had a lesser and more delayed effect. Thirty minutes after the gastric infusions, HR and EE were significantly higher after the sucrose than after the lipid and saline. Hedonic tone was greater and tension lower after the saline and sucrose infusions than after the lipid infusion. From 3 to 3.5 h after ingestion, subjects felt significantly more sleepy after the lipid infusion than they did at these times after the saline infusion, and significantly more dreamy after the lipid infusion than they did after the sucrose infusion. In conclusion, the presence of lipid and sucrose in the intestine induces significant and differing physiological and psychological effects, which are independent of cognitive and orosensory influences.
Publisher: Cambridge University Press (CUP)
Date: 1998
DOI: 10.1079/BJN19980005
Abstract: The effects on mood of reducing dietary fat while keeping the energy constant were examined in ten male and ten female healthy volunteers aged between 20 and 37 years. Each volunteer consumed a diet containing 41% energy as fat for 1 month. For the second month half of the subjects changed to a low-fat diet (25% energy from fat) and the remainder continued to eat the diet containing 41% energy from fat. Changes in mood and blood lipid concentrations were assessed before, during and at the end of the study. Profile of mood states (POMS) ratings of anger–hostility significantly increased in the intervention group after 1 month on the low-fat diet, while during the same period there was a slight decline in anger–hostility in the control subjects (group F 6.72 df 1,14 P = 0.021). Tension–anxiety ratings declined in the control group consuming the higher fat diet but did not change in the group consuming the low-fat diet (group F 6.34 df 1,14 P = 0.025). There was a decline in fasting concentrations of HDL-cholesterol after the low-fat diet and a small increase in subjects consuming the medium-fat diet (group F 4.96 df 1,12 P = 0.046), but no significant changes in concentrations of total serum cholesterol, LDL-cholesterol or triacylglycerol were observed. The results suggest that a change in dietary fat content from 41 to 25% energy may have adverse effects on mood. The alterations in mood appear to be unrelated to changes in fasting plasma cholesterol concentrations.
Publisher: Elsevier BV
Date: 09-2023
Publisher: American Physiological Society
Date: 02-1998
DOI: 10.1152/JAPPL.1998.84.2.507
Abstract: Wells, Anita S., Nicholas W. Read, Chris Idzikowski, and Jane Jones. Effects of meals on objective and subjective measures of daytime sleepiness. J. Appl. Physiol. 84(2): 507–515, 1998.—Effects of recent food ingestion on daytime sleepiness were assessed in 16 subjects (8 men and 8 women) who were each studied on two occasions, 28 days apart. On each occasion, subjects ate a high-fat low-carbohydrate (CHO) (fat/CHO energy ratio 54:41) meal and an isoenergetic low-fat high-CHO meal (fat/CHO energy ratio 7:88) 4 h apart in a counterbalanced order. Sleepiness was measured at 2-h intervals by using the Multiple Sleep Latency Test and the Akerstedt electroencephalograph sleepiness test. To control for circadian factors, one group (4 men, 4 women) ate the meals 2 h later than did the other group of subjects. There were no differences in sleepiness according to the composition of the meal. Sleepiness in the Multiple Sleep Latency Test was significantly greater 1.5 h after the meals were eaten than before ( F 11.37 df 1,15 P = 0.004). Sleepiness was also enhanced in the Akerstedt sleepiness test 3 h 20 min after the meals. The results suggest that the meals induced an enhancement in sleepiness that was not solely due to circadian rhythms.
Publisher: Wiley
Date: 19-12-2020
DOI: 10.1111/OBR.12957
Publisher: Cambridge University Press (CUP)
Date: 07-1995
DOI: 10.1079/BJN19950111
Abstract: The effects of intraduodenal and dietary lipid on alertness, mood and performance in a task requiring sustained attention were investigated in two studies. The first experiment compared the effect of duodenal infusion of either 100 g/l Intralipid (8·36 kJ/min) or isotonic saline (9 g NaCl/l) in paired studies carried out on two non-consecutive days on five male volunteers. Two consecutive 3 h infusions, one of lipid, the other saline, were given blind on each day using a crossover design. Analysis of variance indicated that lipid significantly reduced alertness ( P 0·05) and affected the speed and accuracy of performance in a sustained attention task ( P 0·05). A second experiment compared the effects on eight male volunteers of two isoenergetic lunches of similar appearance, taste and protein content but differing fat and carbohydrate (CHO) contents (fat energy:CHO, 64:18 v . 7:76). Alertness was lower ( P 0·05) and responses to stimuli in a sustained attention task were slower after the high-fat meal than after the low-fat meal ( P 0·05). In conclusion, infusion of lipid into the small intestine, and the substitution of fat for carbohydrate while keeping energy and protein constant in a lunch, both cause an enhanced postprandial decline in alertness and concentration. This may be related to the presence of lipid in the small intestine.
Publisher: Springer Science and Business Media LLC
Date: 19-10-2022
DOI: 10.1186/S12889-022-14252-Z
Abstract: There is increasing focus on moving populations towards healthier and more environmentally sustainable dietary patterns. The Australian Dietary Guidelines provide dietary patterns that promote health and wellbeing. It is unclear how these guidelines align with the more recently published global recommendations of the EAT-Lancet Planetary Health Reference Diet, and how Australian diets compare to both sets of recommendations. Data from one 24-h recall collected for the 2011–13 National Nutrition and Physical Activity Survey were analysed for 5,920 adults aged 19–50 years. Subgroups of this population were identified by diet quality and lower or higher consumption of foods often considered to be environmentally intensive (higher animal meat and dairy foods) or associated with healthiness (higher vegetables and lower discretionary choices). Food group and nutrient composition of Australian diets were compared to diets modelled on the Australian Dietary Guidelines and Planetary Health Reference Diet. The environmental impacts of diets were estimated using an index of combined metrics. Compared with the Planetary Health Reference Diet, the Australian Dietary Guidelines contained more servings of the vegetable, dairy and alternatives, fruit, and discretionary choices. The amount of meat and alternatives was higher in the Planetary Health Reference Diet than Australian Dietary Guidelines due to the inclusion of more plant-based meat alternatives. The average Australian diet contained two to almost four times the Australian Dietary Guidelines and Planetary Health Reference Diet maximum recommended intake of discretionary choices, and provided inadequate amounts of the vegetables, cereals, unsaturated fats and meats and alternatives food groups, primarily due to lower intakes of plant-based alternatives. The average Australian diet also contained less dairy and alternatives than the Australian Dietary Guidelines. In the average Australian diet, red meat and poultry contributed 73% to the total servings of meat and alternatives compared to 33% and 10% for the Australian Dietary Guidelines and Planetary Health Reference Diet respectively. The modelled Australian Dietary Guidelines diet met the relevant nutrient reference value for all 22 nutrients examined, whereas the Planetary Health Reference Diet contained an inadequate amount of calcium. The environmental impact scores of the Planetary Health Reference Diet and Australian Dietary Guidelines were 31% and 46% lower than the average Australian diet. Significant changes are required for Australians’ dietary intake to align more closely with national and global dietary recommendations for health and environmental sustainability.
Publisher: Elsevier BV
Date: 05-1997
DOI: 10.1016/S0031-9384(96)00519-7
Abstract: Paired studies were conducted in 18 healthy volunteers (9 men, 9 women) to investigate whether differences in mood and daytime sleepiness induced by high-fat-low-carbohydrate (CHO) and low-fat-high-CHO morning meals were associated with specific hormonal responses. Plasma insulin concentrations were significantly higher after low-fat-high-CHO meals, and cholecystokinin (CCK) concentrations were significantly higher after high-fat-low-CHO meals. Subjects tended to feel more sleepy and less awake 2-3 h after the high-fat-low-CHO meal, and ratings of fatigue were significantly greater 3 h after the high-fat-low-CHO meal than after the low-fat-high-CHO meal. The results of the present study are consistent with the hypothesis that there is an association between the lassitude experienced after a meal and the release of CCK.
Publisher: Elsevier BV
Date: 06-1996
DOI: 10.1016/0031-9384(95)02253-8
Abstract: Paired studies testing the effects of lower energy high-fat, low-CHO meals (3181 kJ, fat:CHO energy ratio 54:41) and higher energy low-fat, high-CHO meals (3599 kJ, fat:CHO energy ratio 7:88) were conducted in 18 healthy males. The meals were eaten at 1030 h by group A (nine subjects) and 1230 h by group B (nine subjects). Subjective lassitude increased following ingestion of all four meals, but there was little change in performance. In addition, group A, but not group B, felt significantly less vigorous, imaginative, and antagonistic, and significantly more dreamy, feeble, and fatigued after the lower energy high-fat, low-CHO meal than after the higher energy low-fat, high-CHO meal. These results suggest that in the morning, fat exerts a greater depression on alertness and mood than carbohydrate irrespective of a reduction in energy content, but this effect varies according to the time at which food is eaten, and is less evident at lunch time.
Publisher: MDPI AG
Date: 10-04-2023
DOI: 10.3390/NU15081825
Abstract: Sales of plant-based ‘meat’ and ‘milk’—products that mimic the visual and functional characteristics of animal-source foods—have increased rapidly during the past decade and are predicted to continue to increase. As plant-based ‘meat’ and ‘milk’ are nutritionally dissimilar to the animal-source originals, this study aimed to estimate the nutritional implications for the Australian population of substituting ‘Easily Swappable’ animal-source meat and dairy milk with plant-based imitation products. Computer simulation modelling was undertaken using dietary intake data collected in 2011–12 from a nationally representative survey s le. Conservative and Accelerated dietary transition scenarios were modelled in which various amounts of dairy milk and animal-source meat were replaced with plant-based ‘milk’ and plant-based ‘meat’, for the entire population and for various sub-populations. The scenarios were based on sales reports and economic projections. Modelling revealed that the intake of nutrients already at risk of inadequate intake, such as iodine and vitamin B12 (particularly for females), zinc (particularly for males) and n-3 long-chain fatty acids (for adults), would likely be adversely impacted in an Accelerated scenario. In conclusion, widespread replacement of dairy milk and animal-source meat with plant-based ‘milk’ and ‘meat’ may increase the risk of nutritional inadequacies in the Australian population. Messages and policy actions promoting the transition to more environmentally sustainable diets should be designed to avoid such adverse nutritional impacts.
Publisher: American Physiological Society
Date: 09-1996
DOI: 10.1152/AJPGI.1996.271.3.G448
Abstract: The role of endogenous cholecystokinin (CCK) in the regulation of gastric emptying remains controversial. We therefore studied the effect of the CCK-A receptor antagonist loxiglumide on gastric emptying of a high-caloric solid-liquid meal in humans. Gastric emptying was assessed in eight volunteers using intravenous loxiglumide or placebo in a randomized double-blind order. Subjects were studied by a dual-headed gamma camera after ingestion of a pancake (570 kcal) labeled with 99mTc-sulfur colloid and 500 ml 10% glucose containing 111In-diethylenetriamine pentaacetic acid. Plasma CCK was measured by a specific radioimmunoassay. Loxiglumide markedly accelerated gastric emptying of both phases of the meal. The lag period was shortened by 26% (P 0.03) the area under the emptying curve and half-emptying time of solid emptying were lowered by 19 and 24% (P 0.02) and of liquid emptying by 18 and 24% (P 0.04), respectively. Plasma CCK levels were higher during infusion of loxiglumide compared with placebo (P 0.02). These data demonstrate that post-prandially released CCK is a major regulator of gastric emptying of physiological meals containing both solid and liquid components.
Publisher: SAGE Publications
Date: 07-1997
DOI: 10.1177/026988119701100307
Abstract: Previous studies have demonstrated that feelings of sleepiness increase after ingestion of a fat-rich meal. The aim of the study was to test the hypothesis that postprandial sleepiness is mediated by cholecystokinin (CCK) acting on CCK-A receptors. A double-blind crossover study was conducted. Twelve male volunteers ate a high-fat morning meal [54% energy fat, 41% energy carbohydrate (CHO)]. On one day they received an i.v. infusion of Loxiglumide, a CCK-A receptor antagonist (30 mg/kg/h for 10 min then 10 mg/kg/h for 3 h 10 min). On another day the protocol was repeated except a saline placebo infusion was given at similar rates as the Loxiglumide, starting 20 min before the meal. Subjects' mood and sleepiness were monitored throughout using questionnaires and performance tasks. The results indicate that ratings of vigour were significantly lower during the Loxiglumide infusion than during the saline infusion, [ F(1,10)=6.65 p=0.027]. Subjects who were infused with Loxiglumide on their first test day felt significantly (p 0.05) more fatigued, sleepy and tense and less vigorous, less efficient and had lower energetic arousal during the Loxiglumide infusion than during the saline infusion. In conclusion, the results suggest that the postprandial decline in feelings of alertness after a fat-rich meal is not mediated solely by CCK acting through CCK-A receptors.
Publisher: Elsevier BV
Date: 07-1997
DOI: 10.1016/S0031-9384(97)00038-3
Abstract: The aim of this study was to investigate if food could reduce pain perception in a group of 16 healthy human volunteers (8 male and 8 female), and to explore the differential effects of macronutrient composition on the response to cold-induced pain. All subjects underwent the cold pressor test (CPT) on 3 occasions in a counterbalanced order, before and after administration of isoenergetic high-fat low-carbohydrate (CHO) and high-CHO low-fat meals, and when no meal was given. The CPT was carried out 4 times on each test day, once before the meal, and 0.5, 1.5, and 2.5 h after the meal, and at the equivalent times on the day when no food was given. Radial pulse and blood pressure measurements and visual analogue scales of mood/emotional state were carried out before and after each CPT. Mean pain scores were significantly reduced following both meals compared with the no-food condition. The maximum reduction in pain occurred 1.5 h after ingestion, and a significantly greater effect was exerted by the high-fat low-CHO meal compared with the high-CHO low-fat meal. These results demonstrate that food, particularly when rich in fat, significantly reduces the pain induced by the cold pressor stimulus in healthy human subjects.
Publisher: The Royal Australian College of General Practitioners
Date: 04-2021
Publisher: Wiley
Date: 11-2001
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Anita Lawrence.