Vegan Diet and Food Costs Among Adults With Overweight

This secondary analysis of a randomized clinical trial investigates the effects of a vegan diet on total food costs per day.


Introduction
Vegan diets are recognized for numerous health benefits.However, given that food costs may represent a barrier to dietary change, the costs of vegan diets merit examination.
As reported previously in a randomized clinical trial (RCT), 1 an ad libitum low-fat vegan diet resulted in weight loss, improved body composition, and increased insulin sensitivity in overweight adults.This secondary analysis of that RCT assessed food costs.As the prices of staple foods, such as rice and beans, are much lower compared with meat and dairy, it was hypothesized that food costs would be reduced on a vegan diet.

Methods
The methods have been previously described. 1In brief, this randomized, open parallel study was conducted between January 2017 and February 2019 in Washington, DC (trial protocol in Supplement 1).This study followed the CONSORT reporting guideline.The protocol was approved by the Chesapeake institutional review board.All participants provided written informed consent.
Participants were randomly assigned to a vegan or control group in a 1:1 ratio (eFigure in Supplement 2).The vegan group was asked to follow an ad libitum low-fat vegan diet consisting of fruits, vegetables, grains, and legumes, while the control group was requested to make no diet changes.Energy intake and food costs were not limited for either group.At baseline and week 16, a 3-day dietary record (2 weekdays and 1 weekend day) was completed by each participant and analyzed by a registered dietitian certified in the Nutrition Data System for Research. 2r the food cost assessment, intakes from dietary records were linked to a database of national food prices, 3 using the US Department of Agriculture Thrifty Food Plan. 4 Two independent reviewers (C.M. and D.N.), blinded to group assignment, linked it with food groups from the dietary analysis software. 2Linking accuracy was verified by a senior researcher (P.M.), also blinded to group assignment.A repeated measure analysis of variance was used by a statistician blinded to dietary interventions.All significance reporting is 2-sided with type I error of .05.Two-sample t-tests were used to assess the differences between treatment groups, and 1-sample t-tests to assess significance of changes within each group.Statistical analysis was conducted using SAS version 9.4 (SAS Institute) in May 2023.

Results
Of 3115 people screened by telephone, 244 adults with overweight met participation criteria and were randomly assigned to the vegan (

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Vegan Diet and Food Costs Among Adults With Overweight

Figure .
Figure.Changes in Total Food Costs in the Vegan and Control Group From Baseline to Week 16 10.5 White; mean [SD] age, 56.7 [12.8] years) groups.The analysis included 223 (91.0%) participants who completed all aspects of the study, including the final diet records.Mean (95% CI) total food costs per day decreased in the vegan group by approximately 16%, compared with no significant change in the control group.The difference between the groups was significant (Figure, Table).The biggest savings were on meat and dairy.These savings outweighed the increased spending on vegetables, fruits, legumes, whole grains, meat alternatives, and dairy alternatives.

Table .
Changes in Economic Costs From Specific Food Groups at Baseline and Week 16 in the Control and Vegan Groups