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Obesity (Silver Spring). 2019 Mar;27(3):420-426. doi: 10.1002/oby.22389. Epub 2019 Jan 22.

Objective versus Self-Reported Energy Intake Changes During Low-Carbohydrate and Low-Fat Diets.

Author information

1
National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, USA.
2
Department of Medicine, Stanford University, Stanford, California, USA.

Abstract

OBJECTIVE:

This study aimed to compare self-reported with objective measurements of energy intake changes (∆EI) during a 1-year weight-loss intervention with subjects randomized to low-carbohydrate versus low-fat diets.

METHODS:

Repeated body weight measurements were used as inputs to an objective mathematical model to calculate ∆EIModel and to compare with self-reported energy intake changes assessed by repeated 24-hour recalls (∆EIRecall ).

RESULTS:

∆EIRecall indicated a relatively persistent state of calorie restriction of ~500 to 600 kcal/d at 3, 6, and 12 months with no significant differences between the diets. ∆EIModel demonstrated large early decreases in calorie intake > 800 kcal/d followed by an exponential return to ~100 kcal/d below baseline at the end of the year. Accounting for self-reported physical activities did not materially affect the results. Discrepancies between ∆EIModel and ∆EIRecall became progressively greater over time. The low-carbohydrate diet resulted in ∆EIModel that was 162 ± 53 kcal/d lower than the low-fat diet over the first 3 months (P  =  0.002), but no significant diet differences were found thereafter.

CONCLUSIONS:

Self-reported ∆EI measurements were inaccurate. Model-based calculations of ∆EI found that instructions to follow the low-carbohydrate diet resulted in greater calorie restriction than the low-fat diet in the early phases of the intervention, but these diet differences were not sustained.

TRIAL REGISTRATION:

ClinicalTrials.gov NCT01826591.

PMID:
30672127
PMCID:
PMC6392435
DOI:
10.1002/oby.22389
[Indexed for MEDLINE]
Free PMC Article

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