1.
The Effects of Intermittent Fasting and Continuous Energy Restriction with Exercise on Cardiometabolic Biomarkers, Dietary Compliance, and Perceived Hunger and Mood: Secondary Outcomes of a Randomised, Controlled Trial.
Keenan, S, Cooke, MB, Chen, WS, Wu, S, Belski, R
Nutrients. 2022;14(15)
-
-
-
Free full text
Plain language summary
Obesity plays an important role in the development of cardiometabolic diseases. Excess body weight contributes to insulin resistance, unfavourable patterns of blood lipids and systemic inflammation, which are significant risk factors for cardiovascular disease and type 2 diabetes. Lifestyle modifications that restrict energy intake are an effective approach to attaining weight loss and reducing fat mass; however, continuous energy restrictions (CER) often have poor compliance in the long run. Intermittent fasting (IF) approaches present a promising alternative to CER and may promote increased compliance. The favourable changes in cardiometabolic health attained by an energy-restricted diet can be further amplified when combined with exercise. This paper is a secondary analysis from a 12-week intervention investigating the effects of a twice-weekly fast (5:2 IF; IFT group) and CER (CERT group) in 34 young, overweight but metabolically healthy participants when combined with resistance training. The analysis focused on changes in cardiometabolic blood markers, ratings of hunger, mood, energy and compliance as well as the participant's intention to continue with their prescribed diets post-intervention. Both dietary patterns improved blood lipids, namely reductions in total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol over 12 weeks. Reductions in TC and LDL-C were more pronounced in the IFT group. No remarkable differences or changes in triglycerides, the inflammatory marker C-reactive Protein or markers of insulin resistance were seen in either group. Both groups reported high levels of dietary compliance and low levels of hunger, suggesting that both diets are well adhered to in the short to medium term. Some gender-specific differences were seen, but the author was unable to make conclusions due to the small study size. The analysis demonstrated that IF and CER, combined with resistance exercise, can improve some cardiometabolic risk biomarkers in overweight but metabolically healthy adults, independent of weight loss, with greater improvements with IF approaches.
Abstract
(1) Background: Excess weight in the form of adiposity plays a key role in the pathogenesis of cardiometabolic diseases. Lifestyle modifications that incorporate continuous energy restriction (CER) are effective at inducing weight loss and reductions in adiposity; however, prescribing daily CER results in poor long-term adherence. Over the past decade, intermittent fasting (IF) has emerged as a promising alternative to CER that may promote increased compliance and/or improvements in cardiometabolic health parameters independent of weight loss. (2) Methods: This paper presents a secondary analysis of data from a 12-week intervention investigating the effects of a twice-weekly fast (5:2 IF; IFT group) and CER (CERT group) when combined with resistance exercise in 34 healthy participants (17 males and 17 females, mean BMI: 27.0 kg/m2, mean age: 23.9 years). Specifically, changes in cardiometabolic blood markers and ratings of hunger, mood, energy and compliance within and between groups were analysed. Dietary prescriptions were hypoenergetic and matched for energy and protein intake. (3) Results: Both dietary groups experienced reductions in total cholesterol (TC; mean reduction, 7.8%; p < 0.001), low-density lipoprotein cholesterol (LDL-C; mean reduction, 11.1%; p < 0.001) and high-density lipoprotein cholesterol (mean reduction 2.6%, p = 0.049) over the 12 weeks. Reductions in TC and LDL-C were greater in the IFT group after adjustment for baseline levels and change in weight. No significant changes in markers of glucose regulation were observed. Both groups maintained high levels of dietary compliance (~80%) and reported low levels of hunger over the course of the intervention period. (4) Conclusions: Secondary data analysis revealed that when combined with resistance training, both dietary patterns improved blood lipids, with greater reductions observed in the IFT group. High levels of compliance and low reported levels of hunger throughout the intervention period suggest both diets are well tolerated in the short-to-medium term.
2.
A randomised controlled trial of dietary improvement for adults with major depression (the 'SMILES' trial).
Jacka, FN, O'Neil, A, Opie, R, Itsiopoulos, C, Cotton, S, Mohebbi, M, Castle, D, Dash, S, Mihalopoulos, C, Chatterton, ML, et al
BMC medicine. 2017;15(1):23
-
-
-
Free full text
Plain language summary
While extensive observational evidence linking diet quality and mental health exists, a causal relationship between the two has net yet been examined. The aim of this study was to determine the efficacy of a dietary intervention for treating patients with moderate to severe depression. 56 participants were randomised to attend either seven nutritional consultations delivered by a dietitian or social support groups in 12 weeks, and depressive symptomology was assessed at baseline and 12 weeks. This study found that participants receiving the dietary intervention had significantly greater improvements in depression symptoms than the social support group. Based on these results, the authors conclude that dietary improvement is an effective treatment strategy for the management of depression, and that clinicians should consider promoting the benefits of dietary improvement for their patients with depression. Future large-scale studies in this field are needed to better understand the mechanisms underlying this link.
Abstract
BACKGROUND The possible therapeutic impact of dietary changes on existing mental illness is largely unknown. Using a randomised controlled trial design, we aimed to investigate the efficacy of a dietary improvement program for the treatment of major depressive episodes. METHODS 'SMILES' was a 12-week, parallel-group, single blind, randomised controlled trial of an adjunctive dietary intervention in the treatment of moderate to severe depression. The intervention consisted of seven individual nutritional consulting sessions delivered by a clinical dietician. The control condition comprised a social support protocol to the same visit schedule and length. Depression symptomatology was the primary endpoint, assessed using the Montgomery-Åsberg Depression Rating Scale (MADRS) at 12 weeks. Secondary outcomes included remission and change of symptoms, mood and anxiety. Analyses utilised a likelihood-based mixed-effects model repeated measures (MMRM) approach. The robustness of estimates was investigated through sensitivity analyses. RESULTS We assessed 166 individuals for eligibility, of whom 67 were enrolled (diet intervention, n = 33; control, n = 34). Of these, 55 were utilising some form of therapy: 21 were using psychotherapy and pharmacotherapy combined; 9 were using exclusively psychotherapy; and 25 were using only pharmacotherapy. There were 31 in the diet support group and 25 in the social support control group who had complete data at 12 weeks. The dietary support group demonstrated significantly greater improvement between baseline and 12 weeks on the MADRS than the social support control group, t(60.7) = 4.38, p < 0.001, Cohen's d = -1.16. Remission, defined as a MADRS score <10, was achieved for 32.3% (n = 10) and 8.0% (n = 2) of the intervention and control groups, respectively (χ 2 (1) = 4.84, p = 0.028); number needed to treat (NNT) based on remission scores was 4.1 (95% CI of NNT 2.3-27.8). A sensitivity analysis, testing departures from the missing at random (MAR) assumption for dropouts, indicated that the impact of the intervention was robust to violations of MAR assumptions. CONCLUSIONS These results indicate that dietary improvement may provide an efficacious and accessible treatment strategy for the management of this highly prevalent mental disorder, the benefits of which could extend to the management of common co-morbidities. TRIAL REGISTRATION Australia and New Zealand Clinical Trials Register (ANZCTR): ACTRN12612000251820 . Registered on 29 February 2012.