Effect of intermittent versus continuous energy restriction on weight loss, maintenance and cardiometabolic risk: A randomized 1-year trial
Introduction
Obesity has reached epidemic proportions worldwide requiring new approaches [1]. Energy restriction to achieve and maintain a healthy body weight is a cornerstone in the treatment of obesity and concomitant cardiometabolic risk factors, several of which are part of metabolic syndrome [2], [3]. Most recommendations support the use of continuous energy restriction with a consistent daily reduction in energy intake. However, many patients find it difficult to adhere to weight-loss diets given changes in neurobiological pathways favoring weight regain [4]. Recently the notion that intermittent energy restriction may improve dietary adherence has achieved popularity. Intermittent energy restriction typically involves periods of very restricted energy intake or “fasting” interspersed with ad libitum energy intake. This implies that strict adherence is only needed some days a week. The most studied intermittent energy reduction approaches include two days of energy restriction per week [5] or alternate day fasting [6], [7], [8], [9]. On “fasting” days, the dieter typically reduces energy intake to ∼500 kcal/day.
Some data supports the feasibility and even potential physiological benefits of intermittent energy restriction [6], [7]. Findings from short-term studies indicate that participants lose 3–7% of body weight after two to three months of alternate-day fasting with improvements in cardiometabolic risks [7], [8], [9]. The MATADOR study, a randomized trial of obese men examined a less common variant of intermittent energy restriction that alternated two-week-cycles of moderate energy restriction and energy balance [10]. This study showed greater weight and fat loss with intermittent than with continuous energy restriction. Two recent meta-analyses summarized the effects of intermittent energy restriction in intervention studies [11], [12]. Both analyses concluded that neither intermittent nor continuous energy restriction was superior to the other in respect to weight loss. The investigators called for larger long-term trials in order to understand the impact of intermittent energy restriction on weight loss and cardiometabolic risk factors.
Individuals with metabolic syndrome, a clustering of risk factors (circulating triglycerides [TG], glucose, HDL-cholesterol, blood pressure and abdominal obesity), are at high risk of type 2 diabetes and coronary heart disease. Moderate weight loss improves all aspects of metabolic syndrome [13]. Whether intermittent fasting is effective for weight loss and improvements in cardiometabolic risk in such a high risk population is relevant to clinical practice. Thus, we conducted a 1-year, randomized controlled clinical trial to compare the effects of intermittent energy restriction versus continuous energy restriction on weight loss, maintenance and cardiometabolic risk factors in men and women with abdominal obesity and at least one additional component of metabolic syndrome.
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Participants
Men and women aged 21–70 years with body mass index (BMI) 30–45.0 kg/m2 were recruited from August 1, 2015 to April 30, 2016, through advertisement in newspaper and on the face-book page of Oslo University Hospital as well as from patient referrals to the Section of Preventive Cardiology, Department of Endocrinology, Morbid Obesity and Preventive Medicine.
Inclusion criteria included waist circumference ≥94/80 cm (men/women) and ≥1 additional metabolic syndrome component: circulating levels of
Study participants
As shown in the Consolidated Standards of Reporting Trials flow chart four dropouts occurred in the intermittent versus three in the continuous energy restriction group (Fig. 1). None of the participants withdrew due to difficulties adhering to the diet. Baseline characteristics as shown in Table 1 were similarly distributed between the two groups except for TG.
Study outcomes
Changes in body weight and cardiometabolic variables are reported in Table 2. Overall, weight loss was similar among participants in
Discussion
To our knowledge, this is the first randomized, controlled, long-term study of the 5:2 approach to intermittent fasting indicating that intermittent energy restriction is as effective, but not superior to continuous energy restriction at inducing clinically significant weight loss (2) and maintenance and improving cardiometabolic risk factors in free-living men and women with abdominal obesity and at least one additional component of metabolic syndrome. Both diets resulted in equivalent
Statement of author contributions to the manuscript
T.M.S, S.T and M.S designed the study; T.M.S. conducted the dietary counselling and project supervision; T.M.S. analyzed the data; and T.M.S. S.T and M.S. wrote the paper. S.T. had primary responsibility for the final content. All authors read and approved the final manuscript.
Conflict of interest
None.
Acknowledgements
We thank Merete Helgeland MS in Nutrition for assistance with dietary counseling, Sasa Dusanov MD for medical examinations and RMR measurements, Eli Heggen MD PhD and Tor Ole Klemsdal MD PhD for medical examinations, and Ragnhild Kleve and Lise Bergengen for assistance with study procedures.
References (30)
- et al.
Alternate-day fasting and chronic disease prevention: a review of human and animal trials
Am J Clin Nutr
(2007) - et al.
Short-term modified alternate-day fasting: a novel dietary strategy for weight loss and cardioprotection in obese adults
Am J Clin Nutr
(2009) - et al.
Alternate day fasting (ADF) with a high-fat diet produces similar weight loss and cardio-protection as ADF with a low-fat diet
Metabolism
(2013) - et al.
A new predictive equation for resting energy expenditure in healthy individuals
Am J Clin Nutr
(1990) - et al.
Best practice methods to apply to measurement of resting metabolic rate in adults: a systematic review
J Am Dietetic Assoc
(2006) - et al.
Effects of a low glycemic load diet versus a low-fat diet in subjects with and without the metabolic syndrome
Nutr Metab Cardiovasc Dis
(2010) - et al.
Best (but oft forgotten) practices: testing for treatment effects in randomized trials by separate analyses of changes from baseline in each group is a misleading approach
Am J Clin Nutr
(2015 Nov) - et al.
Do intermittent diets provide physiological benefits over continuous diets for weight loss? A systematic review of clinical trials
Mol Cell Endocrinol
(2015 Dec 15) - et al.
Organizational update: the world health organization global status report on noncommunicable disease 2014; one more landmark step in the combat against stroke and vascular disease
Stroke J Cerebral Circ
(2015) - et al.
Guidelines (2013) for the management of overweight and obesity in adults: a report of the American College of Cardiology/American heart Association Task Force on practice guidelines and the obesity Society published by the obesity Society and American College of Cardiology/American heart Association Task Force on practice guidelines. Based on a systematic review from the the obesity expert panel, 2013
Obesity (Silver Spring)
(2014 Jul)
Lifestyle recommendations for the prevention and management of metabolic syndrome: an international panel recommendation
Nutr Rev
Physiological adaptations to weight loss and factors favouring weight regain
Int J Obes
The effects of intermittent or continuous energy restriction on weight loss and metabolic disease risk markers: a randomized trial in young overweight women
Int J Obes
Alternate-day versus daily energy restriction diets: which is more effective for weight loss? a systematic review and meta-analysis
Obes Sci Pract
Intermittent energy restriction improves weight loss efficiency in obese men: the MATADOR study
Int J Obes
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