This pilot study was conducted to assess the consumption and acceptability of whole grain staple foods as a first step in the design of a dietary intervention aiming at lowering markers of T2DM risk among adults in Tanzania. Overall, brown rice, unrefined maize and sorghum ugali were rated favorably in terms of smell, taste, color, appearance, texture, hardness, shine and configuration. Findings from this pilot study demonstrate the feasibility of a longer-term dietary intervention involving consumption of the selected whole grain foods.
White rice and refined maize ugali are currently the most frequently consumed carbohydrates in this population. With the burden of T2DM increasing at a greater rate in urban areas [15, 16], dietary interventions targeting a shift back to traditional whole grain diets may have a major effect in reducing the incidence of DM among adult urban Tanzanians.
Observational studies have found that higher intakes of whole grains and dietary fiber are associated with a reduced risk of T2DM [7, 8], metabolic syndrome and other diet-related chronic diseases [20, 21]. In contrast, refined carbohydrates such as refined maize and white rice, have been strongly associated with the development of T2DM [4, 22]. The main difference between whole and refined grains lies in the preservation of the bran and germ layers in whole grains, which are removed during processing and refinement . Fiber which is concentrated in the bran fraction delays gastric emptying and hence leads to slow release of glucose into circulation [24, 25]. Whole grains also have a higher content of essential fatty acids and various micronutrients such as magnesium, which may also contribute to the observed inverse association between whole grains and DM . Benefits of whole grains on DM risk are hypothesized to be mediated through improved glycemic control, improved insulin sensitivity, reduced inflammation and favorable lipid profiles .
Traditions and customs played a significant role in influencing food choice among residents of Morogoro region, but not in Dar es Salaam, indicating that people from less urbanized settings of Tanzania still value their traditional diets. Consumption of whole grains, such as unrefined maize ugali in Tanzania, has been linked to low socioeconomic status, with persons eating unrefined maize ugali being regarded as poor . As a consequence, majority of people, especially in urban settings, have shifted from consumption of unrefined to refined maize ugali. These findings are supported by another study conducted in Dar es Salaam which showed that white rice intake increases with increasing level of income .
Brown rice, unrefined maize ugali and unrefined sorghum ugali were all rated positively by the participants, indicating that they were acceptable, palatable and well-tolerated. Brown rice is not very common among Tanzanians and only five participants (four from Morogoro and one from Dar es Salaam) reported ever having tried brown rice before. Despite the fact that the majority of participants were tasting brown rice for the first time, responses were generally favorable. It is important to note that nearly all participants were willing to participate in a future dietary intervention study involving the consumption of brown rice, unrefined maize ugali or unrefined sorghum ugali to lower markers of DM risk. Similar findings by our group have been shown in Shanghai China  and Chennai, India , indicating that whole grain substitution of refined grain carbohydrate staples may be a culturally acceptable and feasible intervention strategy to reduce risk of diabetes in high-risk populations in many places around the world.
The main limitation of the current pilot study is its small sample size, which may have resulted in insufficient power to detect gender and regional differences in the acceptability of the unrefined staple dishes. Our analysis also lacks positive control which would have been indeed useful to get a clear picture by having both unrefined and refined carbohydrate foods tested and rated by the participants. While the selected study population is likely to be representative of those at higher risk of DM, it is possible that findings may not be generalizable to the broader Tanzanian population. However, by including the two diverse geographical regions, we were at least able to evaluate people from different socioeconomic and cultural backgrounds.