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The effects of intermittent or continuous energy restriction on weight loss and metabolic disease risk markers: a randomized trial in young overweight women

Six-month randomised trial (n=107 premenopausal women): ~25% energy restriction delivered as intermittent energy restriction (~2710 kJ/day for 2 days/week) versus continuous daily restriction produced similar mean weight loss (−6.4 kg vs −5.6 kg; between-group P=0.4) but modestly greater reductions in fasting insulin and HOMA-IR with intermittent restriction (between-group P=0.04).

Design

  • Population: 107 premenopausal women with overweight/obesity (BMI ~30.6 kg/m²)
  • Arms: IER (~25% total energy deficit as ~2710 kJ/day on 2 days/week) vs CER (~25% deficit spread across 7 days/week; ~6276 kJ/day deficit)
  • Duration: 6 months

Weight and metabolic headline (LOCF; abstract)

  • Weight change: −6.4 kg (95% CI −7.9 to −4.8) IER vs −5.6 kg (95% CI −6.9 to −4.4) CER — P = 0.4 for between-group difference
  • Fasting insulin: between-group difference −1.2 µU/mL (95% CI −1.4 to −1.0; P = 0.04)
  • HOMA insulin resistance: between-group difference −1.2 µU·mmol⁻¹·L⁻¹ (95% CI −1.5 to −1.0; P = 0.04)
  • Other risk markers: abstract reports parallel improvements in leptin, hs-CRP, lipids, and BP across arms

Evidence hygiene

  • 2-day/week severe restriction template—not identical to 16:8 TRE or 5:2 branded apps; place next to time-restricted-eating and intermittent-fasting umbrella reviews already linked.

Publication

Harvie MN, Pegington M, Mattson MP, et al. Int J Obes (Lond). 2011 May;35(5):714-27. PMID 20921964.

Outcomes

  • Body Fat Mass
    Six-month LOCF mean weight change −6.4 kg (95% CI −7.9 to −4.8) with intermittent energy restriction versus −5.6 kg (95% CI −6.9 to −4.4) with continuous restriction; between-group P=0.4 (Harvie et al. 2011).
  • Fasting Insulin
    Between-group difference in fasting insulin −1.2 µU/mL (95% CI −1.4 to −1.0) favouring intermittent versus continuous energy restriction (P=0.04; Harvie et al. 2011).
  • HOMA-IR (Insulin Resistance)
    Between-group difference in HOMA insulin resistance −1.2 µU·mmol⁻¹·L⁻¹ (95% CI −1.5 to −1.0) favouring intermittent versus continuous energy restriction (P=0.04; Harvie et al. 2011).
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