Conclusión del estudio:
La restricción energética intermitente puede
ser una estrategia efectiva para el tratamiento del sobrepeso y la
obesidad. La restricción energética intermitente fue comparable a la
restricción de energía continua para la pérdida de peso a corto plazo en
adultos con sobrepeso y obesos. Se demostró que la restricción energética
intermitente es más efectiva que ningún tratamiento, sin embargo, esto debe
interpretarse con cautela debido al pequeño número de estudios y se justifica
la investigación futura para confirmar los hallazgos de esta revisión.
Comentario personal: Aunque el número
de estudios no es muy alto y debe investigarse más, el resultado de este
metaanálisis está en línea con la propuesta evolutiva y la idea de que la
expresión génica, en nuestra especie, se relaciona con el ejercicio físico
intenso (caza) y con períodos de ayuno (típicos de la exposición al medio
natural en depredadores)
El
estudio original:
Abstract
OBJECTIVE:
To examine the effectiveness of intermittent energy restriction in the
treatment for overweight and obesity in adults, when compared to usual care
treatment or no treatment.
INTRODUCTION:
Intermittent energy restriction encompasses dietary approaches including
intermittent fasting, alternate day fasting, and fasting for two days per week.
Despite the recent popularity of intermittent energy restriction and associated
weight loss claims, the supporting evidence base is limited.
INCLUSION CRITERIA:
This review included overweight or obese (BMI ≥25 kg/m) adults (≥18 years).
Intermittent energy restriction was defined as consumption of ≤800 kcal on at
least one day, but no more than six days per week. Intermittent energy
restriction interventions were compared to no treatment (ad libitum diet) or
usual care (continuous energy restriction
∼25% of recommended energy intake).
Included interventions had a minimum duration of 12 weeks from baseline to post
outcome measurements. The types of studies included were randomized and
pseudo-randomized controlled trials. The primary outcome of this review was
change in body weight. Secondary outcomes included: i) anthropometric outcomes
(change in BMI, waist circumference, fat mass, fat free mass); ii)
cardio-metabolic outcomes (change in blood glucose and insulin, lipoprotein
profiles and blood pressure); and iii) lifestyle outcomes: diet, physical
activity, quality of life and adverse events.
METHODS:
A systematic search was conducted from database inception to November 2015.
The following electronic databases were searched: MEDLINE, Embase, CINAHL,
Cochrane Library, ClinicalTrials.gov, ISRCTN registry, and anzctr.org.au for
English language published studies, protocols and trials. Two independent
reviewers evaluated the methodological quality of included studies using the
standardized critical appraisal instruments from the Joanna Briggs Institute.
Data were extracted from papers included in the review by two independent
reviewers using the standardized data extraction tool from the Joanna Briggs
Institute. Effect sizes were expressed as weighted mean differences and their
95% confidence intervals were calculated for meta-analyses.
RESULTS:
Six studies were included in this review. The intermittent energy
restriction regimens varied across studies and included alternate day fasting,
fasting for two days, and up to four days per week. The duration of studies
ranged from three to 12 months. Four studies included continuous energy
restriction as a comparator intervention and two studies included a no
treatment control intervention. Meta-analyses showed that intermittent energy
restriction was more effective than no treatment for weight loss (-4.14 kg; 95%
CI -6.30 kg to -1.99 kg; p ≤ 0.001). Although both treatment interventions
achieved similar changes in body weight (approximately 7 kg), the pooled
estimate for studies that investigated the effect of intermittent energy
restriction in comparison to continuous energy restriction revealed no
significant difference in weight loss (-1.03 kg; 95% CI -2.46 kg to 0.40 kg;
p = 0.156).
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