Effect of intermittent versus continuous energy restriction on weight loss, maintenance and cardiometabolic risk: A randomized 1-year trial

https://doi.org/10.1016/j.numecd.2018.03.009Get rights and content

Highlights

  • Intermittent and continuous energy restriction resulted in similar weight loss after one year in men and women with obesity.

  • Both diets improved cardiovascular risk factors.

  • Feeling of hunger may limit long-term adherence to intermittent energy restriction.

Abstract

Background & aims

Long-term adherence to conventional weight-loss diets is limited while intermittent fasting has risen in popularity. We compared the effects of intermittent versus continuous energy restriction on weight loss, maintenance and cardiometabolic risk factors in adults with abdominal obesity and ≥1 additional component of metabolic syndrome.

Methods & results

In total 112 participants (men [50%] and women [50%]) aged 21–70 years with BMI 30–45 kg/m2 (mean 35.2 [SD 3.7]) were randomized to intermittent or continuous energy restriction. A 6-month weight-loss phase including 10 visits with dieticians was followed by a 6-month maintenance phase without additional face-to-face counselling. The intermittent energy restriction group was advised to consume 400/600 kcal (female/male) on two non-consecutive days. Based on dietary records both groups reduced energy intake by ∼26–28%. Weight loss was similar among participants in the intermittent and continuous energy restriction groups (8.0 kg [SD 6.5] versus 9.0 kg [SD 7.1]; p = 0.6). There were favorable improvements in waist circumference, blood pressure, triglycerides and HDL-cholesterol with no difference between groups. Weight regain was minimal and similar between the intermittent and continuous energy restriction groups (1.1 kg [SD 3.8] versus 0.4 kg [SD 4.0]; p = 0.6). Intermittent restriction participants reported higher hunger scores than continuous restriction participants on a subjective numeric rating scale (4.7 [SD 2.2] vs 3.6 [SD 2.2]; p = 0.002).

Conclusions

Both intermittent and continuous energy restriction resulted in similar weight loss, maintenance and improvements in cardiovascular risk factors after one year. However, feelings of hunger may be more pronounced during intermittent energy restriction.

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.

Section snippets

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)

  • P. Pérez-Martínez et al.

    Lifestyle recommendations for the prevention and management of metabolic syndrome: an international panel recommendation

    Nutr Rev

    (2017 May 1)
  • F.L.1 Greenway

    Physiological adaptations to weight loss and factors favouring weight regain

    Int J Obes

    (2015)
  • M.N. Harvie et al.

    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

    (2011)
  • B.A. Alhamdan et al.

    Alternate-day versus daily energy restriction diets: which is more effective for weight loss? a systematic review and meta-analysis

    Obes Sci Pract

    (2016)
  • N.M. Byrne et al.

    Intermittent energy restriction improves weight loss efficiency in obese men: the MATADOR study

    Int J Obes

    (2017 Aug 17)
  • Cited by (152)

    • Impact of caloric restriction on the gut microbiota

      2023, Current Opinion in Microbiology
    View all citing articles on Scopus
    View full text