Abstract
Objectives
We sought to assess the effect of daily consumption of macadamia nuts as 15% of calories on body weight, BMI, waist circumference, percent body fat and skeletal muscle mass in overweight/obese men and women with elevated cardiometabolic risk.
Methods
Utilizing a randomized crossover design, we randomized 38 subjects to consume macadamia nuts daily as 15% of calories for 8 weeks (intervention) and their usual diet for 8 weeks (control), with a 2-week washout. Three subjects dropped out early; n = 35 for analysis. Subjects were healthy men and postmenopausal women with a BMI of 25–39, a waist circumference of >101.6 cm for men and >88.9 cm for women, and one additional cardiovascular risk factor (fasting plasma glucose >100 mg/dL, triglycerides ≥150 mg/dl, total cholesterol >200 mg/dL, LDL-C > 100 mg/dL, blood pressure ≥130/85 mmHg or taking anti-hypertensive medication). Macadamia nuts were provided in pre-weighed daily portions as 15% of calories calculated using the Mifflin-St. Jeor equation. Percent body fat and skeletal muscle mass (kg) were determined by bioelectrical impedance analysis. A mixed model analysis was performed with treatment, sequence, phase, and baseline values as fixed-effect terms and subjects as a random-effects term.
Results
Compared to control, consumption of macadamia nuts led to a mean weight change of –348 g (84.13 vs. 83.78 kg; P = 0.15) a mean BMI change of –0.15 kg/m2 (30.61 vs. 30.47 kg/m2; P = 0.12), and a mean waist circumference change of 0.17 cm (107.41 vs. 107.58 cm; P = 0.61). Percent body fat increased by an average of 0.26% after eating nuts (42.70 vs. 42.96%; P = 0.16). Skeletal muscle mass was slightly but significantly lower after eating nuts with a mean change of –0.237 kg (26.33 vs. 26.09 kg; P = 0.017).
Conclusions
Daily consumption of high-fat macadamia nuts for eight weeks in overweight and obese individuals did not change anthropometrics including body weight, BMI, waist circumference, and % body fat. Skeletal muscle mass was slightly lowered but likely not clinically relevant.
Funding Sources
Hort Innovation, Sydney, Australia.
Measurement of Skeletal Muscle mass of Japanese Men and Women Aged 18-84 by Bioelectrical Impedance Analysis Focusing on the Difference in Measured Values Produced by Different Equipment