No Money No Time Culinary Nutrition Website eHealth Challenge: A Pre-Post Evaluation of Impact on Diet Quality, Food Expenditure, and Engagement

No Money No Time (NMNT) is a culinary nutrition website designed to optimize diet quality. The primary aim was to evaluate the impact of an online targeted nutrition challenge email campaign that encouraged engagement with NMNT and goal setting to improve diet quality and weekly food expenditure. A secondary aim was to assess NMNT engagement. Australian adults ≥18 years were recruited to the eHealth nutrition challenge delivered via weekly emails. Diet quality was assessed using the Healthy Eating Quiz (HEQ) diet quality tool. Engagement was assessed using email open and click-through rates. Intention-to-treat (ITT) analysis was conducted using mixed effects linear regression. Of 481 adults (49.7 ± 13.9 years, 84% female) who enrolled 79 (16%) completed the challenge. ITT results indicated statistically significant 6-week increases in diet quality score (+3.8 points <i>p</i> ≤ 0.001, <i>d</i> = 0.58) with sub-scale improvements in vegetables (+0.9 points, <i>p</i> = 0.01, <i>d</i> = 0.32), fruit (+1.2 points, <i>p</i> ≤ 0.001, <i>d</i> = 0.55), and dairy (+0.9 points, <i>p</i> ≤ 0.001, <i>d</i> = 0.58). There were significant post-challenge reductions in household spending on takeaway/snacks/coffee of AUD 8.9 per week (<i>p</i> = 0.01, <i>d</i> = 0.29), body weight reduction (-0.6 kg, <i>p</i> = 0.03, <i>d</i> = 0.26), and BMI (-0.2 kg/m²<i>p</i> = 0.02, <i>d</i> = 0.28). The email open rate remained constant at around 67% (56% to 75%), with an average click-through rate of 18% (7.1% to 37.9%). The eHealth nutrition challenge significantly improved diet quality while reducing BMI and money spent on discretionary foods. Strategies to scale the challenge should be tested as an innovative population strategy for improving diet quality, health indicators, and managing household food budgets.