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.

Nutrients. 2022;14(15)
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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.

Lifestyle medicine

Fundamental Clinical Imbalances : Immune and inflammation
Environmental Inputs : Diet
Personal Lifestyle Factors : Nutrition ; Exercise and movement
Functional Laboratory Testing : Not applicable
Bioactive Substances : Calorie restriction

Methodological quality

Jadad score : Not applicable
Allocation concealment : Not applicable

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