This study provides the first comprehensive food chain study of the trans fat policy context in India and provides insight into the most appropriate interventions to reduce population intakes. It provides a novel overview of the feasibility of reducing trans fat in PHVOs from the perspective of food manufacturers, insight into local food vendor practices and an estimate of trans fat use and consumption in low SES consumers in India.
Trans fat availability in the food supply
Foods and oils containing high amounts of trans and saturated fat remain in the Indian food supply, which has previously been shown in studies in India [32, 33]. This is problematic given that we found that many poor households were frequently consuming these high trans fat snacks. There are no nationally representative samples that examine trans fat intakes in India; however, our study suggests that much like other countries worldwide, there are pockets of the populations – including those who are younger and more socioeconomically disadvantaged – who consume unhealthy levels of trans fat [34, 35]. Therefore a combination of policies that actively target manufacturers, including those in the informal sectors, provides all retailers including low-income food vendors with access to competitively priced oil that contain the organoleptic properties that consumers demand, and improves consumer and vendor awareness of the trans fat content and health impacts of snack foods will be needed.
Policy at the manufacturer level
The most effective way to reduce trans fat availability in the food supply is to ban it. Although there have only been a small number of countries that have been able to enact a ban, this approach to reducing trans fat in the food supply has been successful [6, 9]. Alternatively, countries such as Canada and the United States have been able to significantly lower trans fat levels in the food supply with mandatory trans fat labeling resulting in product reformulation [9, 36–38]. However, the Indian context is very different to other countries that have successfully reduced the trans fat content of foods. Given the sheer scale and diversity of the country, lack of capacity for enforcement and the informal (and largely unregulated) food sector in India , a trans fat ban may not have the anticipated impact on trans fat levels in the Indian food supply. Although ensuring that such policy measures are adequately enforced – and corruption minimized – could improve their effectiveness, additional measures may be needed in order to reduce trans fat availability across the whole food supply.
Although vanaspati manufacturers in India have indicated that it is feasible to reduce trans fat in their products to 10 % they would accomplish this by relying more heavily on palm oil. Although this would likely be associated with improved health outcomes  additional health benefits may be possible with reformulation using oils high in unsaturated fats [1, 40]. They also indicated difficulties in bringing down levels to 5 %. The technology exists to produce products similar in consistency to vanaspati that are trans fat free and relatively low in saturated fat [41, 42]; however, currently widespread adoption has not taken place in India. Increasing investment into development and mass production of cost-effective bakery shortenings and frying oils that have a healthier fatty acid profile and are affordable could be a key way to reduce the use of PHVOs and increase uptake of healthier oils. However, investment in technology will need to be coupled with investment in agricultural supply chains of healthier oils in order to allow manufacturers to replace PHVOs with oils high in unsaturated rather than saturated fat (i.e. alternatives to palm oil). In the 1970s, Brazil increased soybean production substantially by investing public funding for soybean breeding, minimum price supports, production and marketing credit programs, agricultural subsidies, public infrastructure programs and supportive energy and taxation policies . This resulted in soaring production leading to a shift in fat consumption from animal fats to soybean oil . Given that India relies heavily on imports of palm oil due to the low productivity of healthier oils produced domestically, improving inputs into Indian agricultural production is a key policy intervention if trans fat reduction is to succeed .
Policy at the retailer level
We found that many of the vendors in the communities studied were not producing the food themselves but were instead purchasing snacks from wholesalers. Vendors who prepared snacks themselves used various different types of oils, many of which were high in either saturated, trans fat or both. One of the challenges faced by retailers is that the oils they purchase often do not contain nutrition labels making it difficult, if not impossible, for them to make informed purchasing decisions based on the quality of the fat. Although the majority of vendors were not aware of trans fat, even if their awareness increased, they would not be able to choose healthier oils without increased transparency in labeling. This is further compounded by the fact that it appeared that some oils might have been adulterated. For example, the desi ghee sample from the village market had trans fat levels that resembled vanaspati rather than ghee. It is clear from these findings that more needs to be done at the manufacturer level to ensure that oils are labeled correctly.
In order to ensure that both retailers and wholesalers prioritize the quality of the oil used, there is a need to stimulate greater consumer demand for products using healthier oils while potentially concurrently incentivizing manufacturers, wholesalers and retailers to offer new products at comparable costs. This requires coordinated policy action from Public Health, Economic and Business ministries. For example, in Singapore the Health Promotion Board (HPB) began an initiative in 2011 called the Healthier Hawker Program, which aims to reduce the saturated fat content of cooking oils used by food vendors . In order to ensure that there was an affordable supply of healthier oils, the HPB worked with local manufacturing companies to increase the supply of blended oils containing 25 % less saturated fat . In order to cut costs for vendors, they established cooperatives where manufacturers sold and vendors bought these healthier oils. By streamlining this supply chain, it reduced the price, making it a competitive option for vendors. In order to highlight those vendors using the healthier oil, they also adopted a healthier ingredients symbol program – which is part of the program – allows vendors to put up a sign to indicate use of healthier ingredients if trans fat levels are less than 0.5 g/100 g and saturated fat levels are less than 38 g/100 g [46, 47]. A similar initiative could take place in India, particularly in urban areas, to try to increase access to healthier oils by local food vendors. This type of intervention would likely need to take place at the municipal level, which may increase the likelihood of policy uptake. Importantly, the funding for the Singapore Healthy Hawkers program did not come out of the health budget but rather from an economic initiative to support small and medium enterprises [46, 47], pointing to the need to be innovative in terms of identifying opportunities to support multisectoral policy approaches.
Policy at the consumer level
In addition to intervening further upstream in the Indian fats supply chain, interventions aimed at increasing consumer awareness are needed. In the USA and Canada, mandatory trans fat labelling was associated with a significant reduction in the availability of trans fat in the food supply [19, 48–51]. This was aided by increased consumer awareness regarding trans fat. Increased consumer education and trans fat labelling in India is needed alongside the more upstream policy approaches particularly given that products containing trans fat do not always include a nutrition label (i.e., street food). A simple labelling system (such as a trans fat logo) could help increase consumer awareness related to trans fat, thereby increasing consumer demand for use of healthier oils by both manufacturers and vendors.
Although there are many strengths to the multilevel, mixed methods approach used in this study there are also important limitations including the small sample sizes, a limited geographical focus and reliance on household rather than individual level dietary intakes. The small sample size and limited geographical focus have important implications for the generalizability of the study findings. It is likely that trans fat intakes are quite variable across India – additional research examining trans fat intakes, as well as its dietary sources, is required on a larger scale. However, this study provides insight into the main sources of vanaspati consumption and the strategies that would be most effective in addressing its production, sale and consumption in low-income populations in rural Haryana and an urban slum in Delhi.
Lastly, there are inherent limitations to conducting 24-hour dietary recalls including their inability to account for day-to-day variation in intakes . Although we tried to minimize this limitation by conducting dietary recalls on two consecutive days it could have led to reported trans fat intakes that differed from usual intakes.