A diet rich in vegetables provides many nutrients such as vitamins, minerals, and fiber; as a result, eating vegetables could reduce the risk of chronic diseases. However, very few Americans consume enough vegetables daily, and the average intake falls significantly below the national recommendation. Strategies such as changes in vegetable preparation may improve vegetable preference and intake. This first study’s objective was to determine the role of using seasonings compared to steaming on the vegetable purchase, liking, intake, and intention to pay for larger servings. The second study aimed to examine the effectiveness of seasoning and increased portion sizes on vegetable consumption in a US adult population.
An observational study was conducted for two 8-week periods at a university café. Two vegetables were offered each period: green beans/broccoli (2017) and carrots/cauliflower (2018), with options of a standard serving (4-oz), steamed (ST) or seasoned (SS). A survey contained items regarding demographics, previous vegetable choices, lunch habits, vegetable selected, liking, frequency of eating this vegetable, likelihood of preparing, serving size, cost, and eating frequency at café was collected. After determining the role of seasoning in consumer behaviors, a cross-over study of larger serving size was conducted with options of SS or ST green beans, broccoli, cauliflower, and carrots. The sample size was 8-oz, doubled the standard vegetable size (4-oz). Participants returned the questionnaires with information regarding vegetable choice, liking, and demographics. Leftover bowls were weighed for waste analysis. Vegetables were sold at $1.00 for both studies.
Binomial tests showed that there were significantly more SS green beans (n= 90 vs n= 44, p< 0.001), SS broccoli (n= 82 vs n= 54, p= 0.02), and SS cauliflower (n= 65 vs n= 22, p< 0.001) purchased than ST but no significant difference in SS vs ST carrots (n= 38, n= 30). Liking evaluations of preparation methods were high across all vegetables with no preference towards SS or ST (mean= 7.32, range 1-9). All vegetables yielded negligible waste (<6.5 g/bowl); greater than half had 0 g waste. Participants were likely to purchase a larger size (cost the same: 82.1%; cost more: 73.0%).
After the first attempt to seasoning vegetable was conducted, a combined study with larger portion size and seasoning was implemented and showed a similar trend in purchase. According to binomial tests, there were significantly more people purchasing the SS vegetables over ST for all vegetable combined, green beans, broccoli, and cauliflower (p<0.001 for each vegetable type). The total purchase of larger bowls was higher than standard servings in a previous study (527 vs. 437; p=0.004). Vegetable likings were high and similar across all vegetables and cooking methods with an average of 7.25. Overall, 8-oz (226.8g) servings resulted in 16.59 mean g waste and 210.21 mean g of consumption. Independent t-test showed that consumers ate significantly more vegetables than in 4-oz bowls (p<0.001).
Conclusion: Seasoning was associated with more vegetable purchases for three vegetables. Cooking vegetables with herbs and spices was well-accepted by the adult population; participants liked the preparation method that they chose. At the same price, the purchase of larger serving size was higher than standard size; this is true across all vegetable types and preparation methods. The combined methods of seasoning and larger serving size resulted in remarkably higher consumptions of vegetable when compared to standard size.