OBJECTIVE: Ketogenic and Vegan diets have become increasingly popular. The rising popularity of these dietary trends has been met in kind by the food industry producing a variety of specialty ultra-processed foods (UPFs). Despite increasing popularity, the cost and nutrient profile of vegan and ketogenic diets that rely on UPF specialty products is poorly understood. We aimed to assess the cost and nutrient profile of vegan and ketogenic diets that relied primarily on UPFs and compare this to those that relied primarily on whole foods.

DESIGN: We designed and calculated the cost of four one-day meal plans for a hypothetical weight-stable adult female. Two meal plans were created for the vegan-style and ketogenic-style diets respectively with one of each being predominantly whole-food based and the other constituting primarily of UPFs. Carbohydrates were limited to ≤50g, protein was set at 15-20%, and fat ≥75% for the ketogenic meal plans. Carbohydrates were set between 45-65%, protein 15-25% and fat 20-35% for the vegan meal plans. FoodWorks dietary analysis software was used to assess data against the national Australian/New Zealand nutrient reference value (NRV) value for adult females and cost was calculated using Countdown online shopping (a local New Zealand supermarket).

SETTING: New Zealand.

PARTICIPANTS: None.

RESULTS: The whole-food-based meal plans met a greater proportion of the macro and micronutrient thresholds and were less costly when compared with the specialty-based meal plans.

CONCLUSIONS: This study demonstrates that well-planned, predominantly whole-food diets (regardless of dietary trend) are nutritionally superior and more cost-effective than those that rely on UPFs.