Effect of dietary adherence with or without exercise on weight loss: a mechanistic approach to a global problem.
BACKGROUND
Weight loss using low-calorie diets produces variable results, presumably due to a wide range of energy deficits and low-dietary adherence.


OBJECTIVE
Our objective was to quantify the relationship between dietary adherence, weight loss, and severity of caloric restriction.


METHODS
Participants were randomized to diet only, diet-endurance training, or diet-resistance training until body mass index (BMI) was less than 25 kg/m(2).


METHODS
Healthy overweight (BMI 27-30) premenopausal women (n = 141) were included in the study.


METHODS
An 800-kcal/d(-1) diet was provided, and the exercise groups were engaged in three sessions per week.


RESULTS
Dietary adherence, calculated from total energy expenditure determined by doubly labeled water measurements and dual-energy x-ray absorptiometry body composition changes, and degree of caloric restriction were determined.


RESULTS
All groups had similar weight loss (approximately 12.1 +/- 2.5 kg) and length of time to reach target BMI (approximately 158 +/- 70 d). Caloric restriction averaged 59 +/- 9%, and adherence to diet was 73 +/- 34%. Adherence to diet was inversely associated to days to reach target BMI (r = -0.687; P < 0.01) and caloric restriction (r = -0.349; P < 0.01). Association between adherence to diet and percent weight lost as fat was positive for the diet-endurance training (r = 0.364; P < 0.05) but negatively correlated for the diet-only group (r = -0.387; P < 0.05).


CONCLUSIONS
Dietary adherence is strongly associated with rates of weight loss and adversely affected by the severity of caloric restriction. Weight loss programs should consider moderate caloric restriction relative to estimates of energy requirements, rather than generic low-calorie diets.
Del Corral
Pedro
P
Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama 35294-3360, USA. corralp@uab.edu
Chandler-Laney
Paula C
PC
Casazza
Krista
K
Gower
Barbara A
BA
Hunter
Gary R
GR
D015502:Absorptiometry, Photon; D050154:Adiposity / Q000502:physiology; D000328:Adult; D001823:Body Composition / Q000502:physiology; D015992:Body Mass Index; D031204:Caloric Restriction; D004038:Diet, Reducing; D015444:Exercise; D005260:Female; D006801:Humans; D008875:Middle Aged; D010349:Patient Compliance; D010352:Patient Dropouts; D010807:Physical Endurance; D010809:Physical Fitness / Q000502:physiology; D015431:Weight Loss / Q000502:physiology*