Effect of dietary patterns differing in carbohydrate and fat content on blood lipidand glucose profiles based on weight-loss success of breast-cancer survivors

Introduction Healthy body weight is an important factor for prevention of breast cancerrecurrence. Yet, weight loss and weight gain are not currently included inclinical-practice guidelines for posttreatment of breast cancer. The work reportedaddresses one of the questions that must be considered in recommending weight lossto patients: does it matter what diet plan is used, a question of particularimportance because breast cancer treatment can increase risk for cardiovasculardisease. Methods Women who completed treatment for breast cancer were enrolled in a nonrandomized,controlled study investigating effects of weight loss achieved by using twodietary patterns at the extremes of macronutrient composition, although both dietarms were equivalent in protein: high fat, low carbohydrate versus low fat, highcarbohydrate. A nonintervention group served as the control arm; women wereassigned to intervention arms based on dietary preferences. During the 6-monthweight-loss program, which was menu and recipe defined, participants had monthlyclinical visits at which anthropometric data were collected and fasting blood wasobtained for safety monitoring for plasma lipid profiles and fasting glucose.Results from 142 participants are reported. Results Adverse effects on fasting blood lipids or glucose were not observed in eitherdietary arm. A decrease in fasting glucose was observed with progressive weightloss and was greater in participants who lost more weight, but the effect was notstatistically significant, even though it was observed across both diet groups( P = 0.21). Beneficial effects of weight loss on cholesterol (4.7%; P = 0.001), triglycerides (21.8%; P = 0.01), and low-densitylipoprotein (LDL) cholesterol (5.8%; P = 0.06) were observed in bothgroups. For cholesterol ( P = 0.07) and LDL cholesterol ( P =0.13), greater reduction trends were seen on the low-fat diet pattern; whereas,for triglycerides ( P = 0.01) and high-density lipoprotein (HDL)cholesterol ( P = 0.08), a decrease or increase, respectively, was greateron the low-carbohydrate diet pattern. Conclusions Because an individual's dietary preferences can affect dietary adherence andweight-loss success, the lack of evidence of a negative effect of dietary patternon biomarkers associated with cardiovascular risk is an important consideration inthe development of breast cancer practice guidelines for physicians who recommendthat their patients lose weight. Whether dietary pattern affects biomarkers thatpredict long-term survival is a primary question in this ongoing clinicaltrial.