Diet Coaching to Improve Protein Intake in Middle-Aged Women

Abstract

The loss of muscle (mass, strength, and function) occurs in many individuals in their 40’s and begins to accelerate after 50 years of age resulting from multiple understood mechanisms. While many factors are thought to contribute to the changes that are observed in muscle with aging, one significant, yet modifiable factor is dietary protein intake. This study proposed to improve dietary protein intake in a group of middle-aged women living in South Florida over a 12-week period using individualized per-meal protein prescriptions (1.2 g protein/kg body weight evenly distributed for all three meals) provided by a Registered Dietitian, followed by weekly diet coaching from a Nurse Practitioner (coach). Aims included: (1) An examination of the effect of diet coaching on protein intake, nutrition knowledge, muscle mass, strength, and function and (2) An understanding of how diet coaching sessions help in the process of making dietary changes. A parallel mixed methods research design allowed for a synthesis of inferences from each aim resulting in a meta-inference highlighting interdisciplinary collaboration.

An experimental pretest posttest design with randomization to a coached or not coached group occurred. Repeated measures analysis of analyses (RM-ANOVAs) were used to test both the overall (within groups) and intervention effect (between groups) of diet coaching (independent variable) on the following dependent variables: nutrition knowledge, muscle mass, muscle strength, and muscle function between two groups means (coached vs not- coached) over time. Nutrition knowledge scores improved within and between groups with statistical significance. Muscle measurements were not statistically significant between groups, however within groups, significant improvement in lower body muscle strength and function from baseline to end of study was found.

Coached participants were 2.4 times more likely to meet their 3-meal protein prescription and 7.7 times more likely to meet their per-meal breakfast prescription than those who did not receive diet coaching. Qualitative content analysis showcased how consistent support during diet coaching sessions coupled with empowerment of the nutrition knowledge gained led to greater statistically significant increases in the percentage of participants meeting the protein prescription and nutrition knowledge in the group that received diet coaching versus those who did not.