Moira A. Taylor

Regular meal frequency creates more appropriate insulin sensitivity and lipid profiles compared with irregular meal frequency in healthy lean women

Objective: To investigate the impact of irregular meal frequency on circulating lipids, insulin, glucose and uric acid concentrations which are known cardiovascular risk factors.Design: A randomised crossover dietary intervention study.Setting: Nottingham, UK—Healthy free-living women.Subjects: A total of nine lean healthy women aged 18–42 y recruited via advertisement.Intervention: A randomised crossover trial with two phases of 14 days each. In Phase 1, subjects consumed their normal diet on either 6 occasions per day (regular) or by following a variable meal frequency (3–9 meals/day, irregular). In Phase 2, subjects followed the alternative meal pattern to that followed in Phase 1, after a 2-week (wash-out) period. Subjects were asked to come to the laboratory after an overnight fast at the start and end of each phase. Blood samples were taken for measurement of circulating glucose, lipids, insulin and uric acid concentrations before and for 3 h after consumption of a high-carbohydrate test meal.Results: Fasting glucose and insulin values were not affected by meal frequency, but peak insulin and AUC of insulin responses to the test meal were higher after the irregular compared to the regular eating patterns (P<0.01). The irregular meal frequency was associated with higher fasting total (P<0.01) and LDL (P<0.05) cholesterol.Conclusion: The irregular meal frequency appears to produce a degree of insulin resistance and higher fasting lipid profiles, which may indicate a deleterious effect on these cardiovascular risk factors.Sponsorship: The Ministry of Health and Medical Education, IR Iran.

Breakfast Consumption Affects Appetite, Energy Intake, and the Metabolic and Endocrine Responses to Foods Consumed Later in the Day in Male Habitual Breakfast Eaters

The effects of breakfast consumption on energy intake and the responses to foods consumed later in the day remain unclear. Twelve men of healthy body weight who reported regularly consuming breakfast (mean ± SD age 23.4 ± 7.3 y; BMI 23.5 ± 1.7 kg/m(2)) completed 2 trials using a randomized crossover design. Participants were provided with a 1050-kJ liquid preload 150 min after consuming a standardized breakfast (B) (10% daily energy requirement and 14, 14, and 72% energy from protein, fat, and carbohydrate, respectively), or no breakfast (NB). Blood glucose and serum insulin responses to the preload (area under the curve) were higher in the NB condition (P < 0.05). Plasma FFA responses to the preload were higher in the NB condition (P < 0.01). Plasma glucagon-like peptide 1 (P < 0.01) and plasma peptide Y (P < 0.05) responses were higher after the preload in the B condition. Desire to eat, fullness, and hunger ratings collected immediately prior to consuming the preload were all different from the fasting values in the NB condition (P < 0.05). Thus, immediately prior to consuming the preload, the fullness rating was lower and hunger and desire to eat ratings were higher in the NB condition (P < 0.05). Energy intake at the lunchtime test meal was ~17% lower in the B condition (P < 0.01). In conclusion, missing breakfast causes metabolic and hormonal differences in the responses to foods consumed later in the morning as well as differences in subjective appetite and a compensatory increase in energy intake.

Timing of the introduction of complementary feeding and risk of childhood obesity: a systematic review.

The World Health Organisation recommends exclusive breastfeeding until 6 months of age and continued breastfeeding until 2 years of age or beyond. Appropriate complementary foods should be introduced in a timely fashion, beginning when the infant is 6 months old. In developing countries, early or inappropriate complementary feeding may lead to malnutrition and poor growth, but in countries such as the United Kingdom and United States of America, where obesity is a greater public health concern than malnutrition, the relationship to growth is unclear. We conducted a systematic review of the literature that investigated the relationship between the timing of the introduction of complementary feeding and overweight or obesity during childhood. Electronic databases were searched from inception until 30 September 2012 using specified keywords. Following the application of strict inclusion/exclusion criteria, 23 studies were identified and reviewed by two independent reviewers. Data were extracted and aspects of quality were assessed using an adapted Newcastle–Ottawa scale. Twenty-one of the studies considered the relationship between the time at which complementary foods were introduced and childhood body mass index (BMI), of which five found that introducing complementary foods at <3 months (two studies), 4 months (2 studies) or 20 weeks (one study) was associated with a higher BMI in childhood. Seven of the studies considered the association between complementary feeding and body composition but only one study reported an increase in the percentage of body fat among children given complementary foods before 15 weeks of age. We conclude that there is no clear association between the timing of the introduction of complementary foods and childhood overweight or obesity, but some evidence suggests that very early introduction (at or before 4 months), rather than at 4–6 months or >6 months, may increase the risk of childhood overweight.

Association between Faecalibacterium prausnitzii and dietary fibre in colonic fermentation in healthy human subjects

The intestinal microbiota are a complex ecosystem influencing the immunoregulation of the human host, providing protection from colonising pathogens and producing SCFA as the main energy source of colonocytes. Our objective was to investigate the effect of dietary fibre exclusion and supplementation on the intestinal microbiota and SCFA concentrations. Faecal samples were obtained from healthy volunteers before and after two 14 d periods of consuming formulated diets devoid or supplemented with fibre (14 g/l). The faecal microbiota were analysed using fluorescent in situ hybridisation and SCFA were measured using GLC. There were large and statistically significant reductions in the numbers of the Faecalibacterium prausnitzii (P < or = 0.01) and Roseburia spp. (P < or = 0.01) groups during both the fibre-free and fibre-supplemented diets. Significant and strong positive correlations between the proportion of F. prausnitzii and the proportion of butyrate during both baseline normal diets were found (pre-fibre free r 0.881, P = 0.001; pre-fibre supplemented r 0.844, P = 0.002). A significant correlation was also found between the proportional reduction in F. prausnitzii and the proportional reduction in faecal butyrate during both the fibre-free (r 0.806; P = 0.005) and the fibre-supplemented diet (r 0.749; P = 0.013). These findings may contribute to the understanding of the association between fibre, microbiota and fermentation in health, during enteral nutrition and in disease states such as Crohns disease.

Effects of dietary intervention and quadriceps strengthening exercises on pain and function in overweight people with knee pain: randomised controlled trial

Objective To determine whether dietary intervention or knee strengthening exercise, or both, can reduce knee pain and improve knee function in overweight and obese adults in the community. Design Pragmatic factorial randomised controlled trial. Setting Five general practices in Nottingham. Participants 389 men and women aged 45 and over with a body mass index (BMI) of ≥28.0 and self reported knee pain. Interventions Participants were randomised to dietary intervention plus quadriceps strengthening exercises; dietary intervention alone; quadriceps strengthening exercises alone; advice leaflet only (control group). Dietary intervention consisted of individualised healthy eating advice that would reduce normal intake by 2.5 MJ (600 kcal) a day. Interventions were delivered at home visits over a two year period. Main outcome measures The primary outcome was severity of knee pain scored with the Western Ontario McMaster (WOMAC) osteoarthritis index at 6, 12, and 24 months. Secondary outcomes (all at 24 months) included WOMAC knee physical function and stiffness scores and selected domains on the SF-36 and the hospital anxiety and depression index. Results 289 (74%) participants completed the trial. There was a significant reduction in knee pain in the knee exercise groups compared with those in the non-exercise groups at 24 months (percentage risk difference 11.61, 95% confidence interval 1.81% to 21.41%). The absolute effect size (0.25) was moderate. The number needed to treat to benefit from a ≥30% improvement in knee pain at 24 months was 9 (5 to 55). In those randomised to knee exercise improvement in function was evident at 24 months (mean difference −3.64, −6.01 to −1.27). The mean difference in weight loss at 24 months in the dietary intervention group compared with no dietary intervention was 2.95 kg (1.44 to 4.46); for exercise versus no exercise the difference was 0.43 kg (−0.82 to 1.68). This difference in weight loss was not associated with improvement in knee pain or function but was associated with a reduction in depression (absolute effect size 0.19). Conclusions A home based, self managed programme of simple knee strengthening exercises over a two year period can significantly reduce knee pain and improve knee function in overweight and obese people with knee pain. A moderate sustained weight loss is achievable with dietary intervention and is associated with reduced depression but is without apparent influence on pain or function. Trial registration Current Controlled Trials ISRCTN 93206785.

Decreased thermic effect of food after an irregular compared with a regular meal pattern in healthy lean women

OBJECTIVES: To investigate the impact of irregular meal frequency on body weight, energy intake, appetite and resting energy expenditure in healthy lean women.DESIGN: Nine healthy lean women aged 18–42 y participated in a randomised crossover trial consisting of three phases over a total of 43 days. Subjects attended the laboratory at the start and end of phases 1 and 3. In Phase 1 (14 days), subjects were asked to consume similar things as normal, but either on 6 occasions per day (regular meal pattern) or follow a variable predetermined meal frequency (between 3 and 9 meals/day) with the same total number of meals over the week. In Phase 2 (14 days), subjects continued their normal diet as a wash-out period. In Phase 3 (14 days), subjects followed the alternative meal pattern to that followed in Phase 1. Subjects recorded their food intake for three predetermined days during the irregular period when they were eating 9, 3 and 6 meals/day. They also recorded their food intake on the corresponding days during the regular meal pattern period. Subjects fasted overnight prior to each laboratory visit, at which fasting resting metabolic rate (RMR) was measured by open-circuit indirect calorimetry. Postprandial metabolic rate was then measured for 3 h after the consumption of a milkshake test meal (50% CHO, 15% protein and 35% fat of energy content). Subjects rated appetite before and after the test meal.RESULTS: There were no significant differences in body weight and 3-day mean energy intake between the regular and irregular meal pattern. In the irregular period, the mean energy intake on the day when 9 meals were eaten was significantly greater than when 6 or 3 meals were consumed (P=0.0001). There was no significant difference between the 3 days of the regular meal pattern. Subjective appetite measurement showed no significant differences before and after the test meal in all visits. Fasting RMR showed no significant differences over the experiment. The overall thermic effect of food (TEF) over the 3 h after the test meal was significantly lower after the irregular meal pattern (P=0.003).CONCLUSION: Irregular meal frequency led to a lower postprandial energy expenditure compared with the regular meal frequency, while the mean energy intake was not significantly different between the two. The reduced TEF with the irregular meal frequency may lead to weight gain in the long term.

Genetic Polymorphisms and Weight Loss in Obesity: A Randomised Trial of Hypo-Energetic High- versus Low-Fat Diets

Objectives: To study if genes with common single nucleotide polymorphisms (SNPs) associated with obesity-related phenotypes influence weight loss (WL) in obese individuals treated by a hypo-energetic low-fat or high-fat diet. Design: Randomised, parallel, two-arm, open-label multi-centre trial. Setting: Eight clinical centres in seven European countries. Participants: 771 obese adult individuals. Interventions: 10-wk dietary intervention to hypo-energetic (−600 kcal/d) diets with a targeted fat energy of 20%–25% or 40%–45%, completed in 648 participants. Outcome Measures: WL during the 10 wk in relation to genotypes of 42 SNPs in 26 candidate genes, probably associated with hypothalamic regulation of appetite, efficiency of energy expenditure, regulation of adipocyte differentiation and function, lipid and glucose metabolism, or production of adipocytokines, determined in 642 participants. Results: Compared with the noncarriers of each of the SNPs, and after adjusting for gender, age, baseline weight and centre, heterozygotes showed WL differences that ranged from −0.6 to 0.8 kg, and homozygotes, from −0.7 to 3.1 kg. Genotype-dependent additional WL on low-fat diet ranged from 1.9 to −1.6 kg in heterozygotes, and from 3.8 kg to −2.1 kg in homozygotes relative to the noncarriers. Considering the multiple testing conducted, none of the associations was statistically significant. Conclusions: Polymorphisms in a panel of obesity-related candidate genes play a minor role, if any, in modulating weight changes induced by a moderate hypo-energetic low-fat or high-fat diet.

Randomized, multi-center trial of two hypo-energetic diets in obese subjects: high- versus low-fat content

Objective:To investigate whether a hypo-energetic low-fat diet is superior to a hypo-energetic high-fat diet for the treatment of obesity.Design:Open-label, 10-week dietary intervention comparing two hypo-energetic (−600 kcal/day) diets with a fat energy percent of 20–25 or 40–45.Subjects:Obese (BMI ⩾30 kg/m2) adult subjects (n=771), from eight European centers.Measurements:Body weight loss, dropout rates, proportion of subjects who lost more than 10% of initial body weight, blood lipid profile, insulin and glucose.Results:The dietary fat energy percent was 25% in the low-fat group and 40% in the high-fat group (mean difference: 16 (95% confidence interval (CI) 15–17)%). Average weight loss was 6.9 kg in the low-fat group and 6.6 kg in the high-fat group (mean difference: 0.3 (95% CI −0.2 to 0.8) kg). Dropout was 13.6% (n=53) in the low-fat group and 18.3% (n=70) in the high-fat group (P=0.001). Among completers, more subjects lost >10% in the low-fat group than in the high-fat group ((20.8%, n=70) versus (14.7%, n=46), P=0.02). Fasting plasma total, low-density lipoprotein- and high-density lipoprotein-cholesterol decreased in both groups, but more so in the low-fat group than in the high-fat group. Fasting plasma insulin and glucose were lowered equally by both diets.Conclusions:The low-fat diet produced similar mean weight loss as the high-fat diet, but resulted in more subjects losing >10% of initial body weight and fewer dropouts. Both diets produced favorable changes in fasting blood lipids, insulin and glucose.

Randomized trial of the effects of cholesterol-lowering dietary treatment on psychological function.

PURPOSE Epidemiological studies have suggested that cholesterol lowering could affect psychological functioning. This study was designed to test whether cholesterol-lowering diets adversely affect mood and cognitive function.5.2 mM [198 mg/dL]) to either a low-fat diet, a Mediterranean diet, or a waiting-list control. Cholesterol levels, psychological well-being (depression, anxiety, hostility), and cognitive function were assessed at baseline, 6 weeks, and 12 weeks. RESULTS Total serum cholesterol levels fell significantly more in the intervention groups (8.2% reduction) than in the control group (P <0.001). All three groups showed a modest improvement in psychological well-being during the 12-week treatment period, but there were no differences among the groups. There were no between-group differences on three measures of cognitive function, but for a fourth measure, which involved the task with the greatest processing load, the two intervention groups did significantly worse (P <0.001) than the control group. The change in performance was correlated with the change in total serum cholesterol level (r = 0. 21, P = 0.01). CONCLUSIONS Two dietary interventions that successfully lowered serum cholesterol levels had no adverse effect on mood. There was some evidence for a relative impairment in cognitive function in the treated groups in one of four cognitive tests, but additional studies will be required to determine the relevance of this finding.

Compared with nibbling, neither gorging nor a morning fast affect short-term energy balance in obese patients in a chamber calorimeter

OBJECTIVE: To test if a diet of 4.2 MJ/24 h as six isocaloric meals would result in a lower subsequent energy intake, or greater energy output than (a) 4.2 MJ/24 h as two isocaloric meals or (b) a morning fast followed by free access to food.DESIGN: Subjects were confined to the Metabolic Unit from 19:00 h on day 1 to 09:30 h on day 6. Each day they had a fixed diet providing 4.2 MJ with three pairs of meal patterns which were offered in random sequence. They were: six meals vs two meals without access to additional foods (6vs2), or six meals vs 2 meals with access to additional food (6+vs2+), or six meals vs four meals (6+vsAMFAST). In the AMFAST condition the first two meals of the day were omitted to reduce daily intake to 2.8 MJ and to create a morning fast, but additional food was accessible thereafter. Patients were confined in the chamber calorimeter from 19:00 h on day 2 until 09:00 h on day 4, and then from 19:00 h on day 4 to 09:00 h on day 6. The order in which each meal pattern was offered was balanced over time.MEASUREMENTS: Energy expenditure (chamber calorimetry), spontaneous activity (video) and energy intake (where additional foods were available) during the final 24 h of each dietary component.SUBJECTS: Ten (6vs2), eight (6+vs2+) and eight (6+vsAMFAST) women were recruited who had a BMI of greater than 25 kg/m2.RESULTS: From experiment 6vs2 the difference between energy expenditure with six meals (10.00 MJ) and two meals (9.96 MJ) was not significant (P=0.88). Energy expenditure between 23:00 h and 08:00 h (‘night’) was, however, significantly higher (P=0.02) with two meals (9.12 MJ/24 h) compared with six meals (8.34 MJ/24 h). The pattern of spontaneous physical activity did not differ significantly between these two meal patterns (P>0.05). Total energy intake was affected by neither meal frequency in experiment 6+vs2+ (10.75 MJ with six, 11.08 MJ with two; P=0.58) nor a morning fast in experiment 6+vsAMFAST (8.55 MJ/24 h with six, 7.60 MJ with AMFAST; P=0.40). The total diet of subjects who had a morning fast tended to have a lower percentage of total energy from carbohydrate (40%) than when they had six meals per 24 h (49%) (P=0.05). Subsequent energy balance was affected by neither meal frequency (6vs2; P=0.88, 6+vs2+; P=0.50) nor a morning fast (P=0.18).CONCLUSIONS: In the short term, meal frequency and a period of fasting have no major impact on energy intake or expenditure but energy expenditure is delayed with a lower meal frequency compared with a higher meal frequency. This might be attributed to the thermogenic effect of food continuing into the night when a later, larger meal is given. A morning fast resulted in a diet which tended to have a lower percentage of energy from carbohydrate than with no fast.International Journal of Obesity (2001) 25, 519–528