PURPOSE: Several studies have reported seasonal variation in intake of food groups and certain nutrients. However, whether this could lead to a seasonal pattern of diet quality has not been addressed. We aimed to describe the seasonality of diet quality, and to examine the contribution of the food groups included in the dietary guidelines to this seasonality.METHODS: Among 9701 middle-aged and elderly participants of the Rotterdam Study, a prospective population-based cohort, diet was assessed using food-frequency questionnaires (FFQ). Diet quality was measured as adherence to the Dutch dietary guidelines, and expressed in a diet quality score ranging from 0 to 14 points. The seasonality of diet quality and of the food group intake was examined using cosinor linear mixed models. Models were adjusted for sex, age, cohort, energy intake, physical activity, body mass index, comorbidities, and education.RESULTS: Diet quality had a seasonal pattern with a winter-peak (seasonal variation = 0.10 points, December-peak) especially among participants who were men, obese and of high socio-economic level. This pattern was mostly explained by the seasonal variation in the intake of legumes (seasonal variation = 3.52 g/day, December-peak), nuts (seasonal variation = 0.78 g/day, January-peak), sugar-containing beverages (seasonal variation = 12.96 milliliters/day, June-peak), and dairy (seasonal variation = 17.52 g/day, June-peak).CONCLUSIONS: Diet quality varies seasonally with heterogeneous seasonality of food groups counteractively contributing to the seasonal pattern in diet quality. This seasonality should be considered in future research on dietary behavior. Also, season-specific recommendations and policies are required to improve diet quality throughout the year.
Aims: This systematic review and meta-analysis evaluates the additional effect of exercise to hypocaloric diet on body weight, body composition, glycaemic control and cardio-respiratory fitness in adults with overweight or obesity and type 2 diabetes. Methods: Embase, Medline, Web of Science and Cochrane Central databases were evaluated, and 11 studies were included. Random-effects meta-analysis was performed on body weight and measures of body composition and glycaemic control, to compare the effect of hypocaloric diet plus exercise with hypocaloric diet alone. Results: Exercise interventions consisted of walking or jogging, cycle ergometer training, football training or resistance training and duration varied from 2 to 52 weeks. Body weight and measures of body composition and glycaemic control decreased during both the combined intervention and hypocaloric diet alone. Mean difference in change of body weight (−0.77 kg [95% CI: −2.03; 0.50]), BMI (−0.34 kg/m2 [95% CI: −0.73; 0.05]), waist circumference (−1.42 cm [95% CI: −3.84; 1.00]), fat-free mass (−0.18 kg [95% CI: −0.52; 0.17]), fat mass (−1.61 kg [95% CI: −4.42; 1.19]), fasting glucose (+0.14 mmol/L [95% CI: −0.02; 0.30]), HbA1c (−1 mmol/mol [95% CI: −3; 1], −0.1% [95% CI: −0.2; 0.1]) and HOMA-IR (+0.01 [95% CI: −0.40; 0.42]) was not statistically different between the combined intervention and hypocaloric diet alone. Two studies reported VO2max and showed significant increases upon the addition of exercise to hypocaloric diet. Conclusions: Based on limited data, we did not find additional effects of exercise to hypocaloric diet in adults with overweight or obesity and type 2 diabetes on body weight, body composition or glycaemic control, while cardio-respiratory fitness improved.
BACKGROUND: Intentional weight loss in obese older adults is a risk factor for accelerated muscle mass loss. We investigated whether a high protein diet and/or resistance exercise preserves fat free mass (FFM) during weight loss in overweight and obese older adults.METHODS: We included 100 overweight and obese adults (55-80 year) in a randomized controlled trial (RCT) with a 2 × 2 factorial design and intention-to-treat analysis. During a 10-week weight loss program all subjects followed a hypocaloric diet. Subjects were randomly allocated to either a high protein (1.3 g/kg body weight) or normal protein diet (0.8 g/kg), with or without a resistance exercise program 3 times/week. FFM was assessed by air displacement plethysmography.RESULTS: At baseline, mean (±SD) BMI was 32 ± 4 kg/m(2). During intervention, protein intake was 1.13 ± 0.35 g/kg in the high protein groups vs. 0.98 ± 0.29 in the normal protein groups, which reflects a 16.3 ± 5.2 g/d higher protein intake in the high protein groups. Both high protein diet and exercise did not significantly affect change in body weight, FFM and fat mass (FM). No significant protein*exercise interaction effect was observed for FFM. However, within-group analysis showed that high protein in combination with exercise significantly increased FFM (+0.6 ± 1.3 kg, p = 0.011).CONCLUSION: A high protein diet, though lower than targeted, did not significantly affect changes in FFM during modest weight loss in older overweight and obese adults. There was no significant interaction between the high protein diet and resistance exercise for change in FFM. However, only the group with the combined intervention of high protein diet and resistance exercise significantly increased in FFM.TRIAL REGISTRATION: Dutch Trial Register, number NTR4556, date 05-01-2014.
