The proposed “incentive hope” hypothesis is highly relevant to the global obesity epidemic and its accompanying adverse consequences on population health (GBD 2015 Obesity Collaborators Reference Afshin, Forouzanfar, Reitsma, Sur, Estep, Lee, Marczak, Mokdad, Moradi-Lakeh, Naghavi, Salama, Vos, Abate, Abbafati, Ahmed, Al-Aly, Alkerwi, Al-Raddadi, Amare, Amberbir, Amegah, Amini, Amrock, Anjana, Ärnlöv, Asayesh, Banerjee, Barac, Baye, Bennett, Beyene, Biadgilign, Biryukov, Bjertness, Boneya, Campos-Nonato, Carrero, Cecilio, Cercy, Ciobanu, Cornaby, Damtew, Dandona, Dandona, Dharmaratne, Duncan, Eshrati, Esteghamati, Feigin, Fernandes, Fürst, Gebrehiwot, Gold, Gona, Goto, Habtewold, Hadush, Hafezi-Nejad, Hay, Horino, Islami, Kamal, Kasaeian, Katikireddi, Kengne, Kesavachandran, Khader, Khang, Khubchandani, Kim, Kim, Kinfu, Kosen, Ku, Defo, Kumar, Larson, Leinsalu, Liang, Lim, Liu, Lopez, Lozano, Majeed, Malekzadeh, Malta, Mazidi, McAlinden, McGarvey, Mengistu, Mensah, Mensink, Mezgebe, Mirrakhimov, Mueller, Noubiap, Obermeyer, Ogbo, Owolabi, Patton, Pourmalek, Qorbani, Rafay, Rai, Ranabhat, Reinig, Safiri, Salomon, Sanabria, Santos, Sartorius, Sawhney, Schmidhuber, Schutte, Schmidt, Sepanlou, Shamsizadeh, Sheikhbahaei, Shin, Shiri, Shiue, Roba, Silva, Silverberg, Singh, Stranges, Swaminathan, Tabarés-Seisdedos, Tadese, Tedla, Tegegne, Terkawi, Thakur, Tonelli, Topor-Madry, Tyrovolas, Ukwaja, Uthman, Vaezghasemi, Vasankari, Vlassov, Vollset, Weiderpass, Werdecker, Wesana, Westerman, Yano, Yonemoto, Yonga, Zaidi, Zenebe, Zipkin and Murray2017). In the present commentary we expand and bring in alternative views from two perspectives, (a) the socioeconomic perspective and (b) the physiological perspective, including neurological and genetic factors. Both can have a role in the development of obesity.

It is plausible that poverty-related food insecurity represents both economic and nutritional uncertainty. Such uncertainty, in some situations, could lead to a desire for more energy-dense, filling, and satisfying foods. The foods’ reward value could be mediated by individual genetic programming and variation (Qasim et al. Reference Qasim, Turcotte, de Souza, Samaan, Champredon, Dushoff, Speakman and Meyre2018).

Although obesity is far more prevalent among populations with lower education and incomes and living in more deprived neighborhoods, middle-income groups and even high-income groups are not totally spared (Hruby & Hu Reference Hruby and Hu2015). In other words, obesity and type 2 diabetes also occur among groups of higher socioeconomic status (SES) where material deprivation or lack of resources to purchase nutritious foods is not at issue (Chan Reference Chan2016).

This access to economic resources by higher-SES groups removes food uncertainty as understood in the context of the animal studies discussed in the target article (i.e., need to forage or hunt). What does characterize food choices of lower-SES groups is the selection of low-cost foods that are typically rich in energy but can have minimal nutritional value (Pechey et al. Reference Pechey, Jebb, Kelly, Almiron-Roig, Conde, Nakamura, Shemilt, Suhrcke and Marteau2013). In general, the widespread availability of palatable low-cost, energy-dense foods has been associated with rising obesity rates both in high-income and in low- and middle-income countries and societies. The reward value of energy-dense foods can have a strong neural component.

Preferences for high-energy-density (high-ED) foods are a strong determinant of food choices, mostly linked with fatty and sweet taste preferences present from birth (Chmurzynska & Mlodzik Reference Chmurzynska and Mlodzik2017; Mennella & Bobowski Reference Mennella and Bobowski2015). In addition, overconsumption of particularly high-ED foods (e.g., processed, extracaloric snacks, meals, and desserts) could respond to an evolutionary discordance, that is, a poor adaptation to detect calories in foods that have a historically unusual (high) ED (Brunstrom et al. Reference Brunstrom, Drake, Forde and Rogers2018). This may be because, as early humans, we adapted to discriminate between low (e.g., plants)- and high (e.g., meat)-ED foods to make foraging more cost-effective, thanks in part to basic taste characteristics. However, in the current hypercaloric food environment, this level of discrimination is not sufficient and leads to the consumption of extra calories (Ziauddeen et al. Reference Ziauddeen, Page, Penney, Nicholson, Kirk and Almiron-Roig2018).

In addition to sensory attributes potentially misleading our food choices, food decisions may be driven by negative processes occurring at the neuropsychological level, ranging from executive function impairment, expressed in deficient inhibition and cognitive inflexibility, to behaviors including implicit motivation and impulsivity (Medic et al. Reference Medic, Ziauddeen, Forwood, Davies, Ahern, Jebb, Marteau and Fletcher2016). In the selection of convenient food choices, not only prefrontal regions, but also the neural communication between the lateral hypothalamus and corticostriatal regions determined by the metabolic state, are functionally relevant (Huerta et al. Reference Huerta, Sarkar, Duong, Laird and Fox2014). The dopaminergic system in particular may play a key role in reward-related food intake and with behaviors necessary for feeding to maintain survival (Suzuki et al. Reference Suzuki, Jayasena and Bloom2012), but also with motivation (Salamone et al. Reference Salamone, Pardo, Yohn, López-Cruz, SanMiguel and Correa2015) and risk-taking behavior (Arrondo et al. Reference Arrondo, Aznárez-Sanado, Fernández-Seara, Goñi, Loayza, Salamon-Klobut, Heukamp and Pastor2015).

These traits, which typically occur in overweight individuals, combined with a “temptations-loaded” food environment, are likely to be determining factors for the development of obesity among higher-SES groups. There is also a higher level of control that is related to keeping long-term goals not found in animals, for example, a concern for body image (Yiu et al. Reference Yiu, Murray, Arlt, Eneva and Chen2017).

Overall, energy homeostasis depends on energy intake and expenditure, which are regulated by exogenous (e.g., food availability and environmental conditions) and endogenous (e.g., there are genes regulating appetite, taste, and olfaction) factors. Furthermore, the neuroendocrine balance is influenced by an individual's genetic variant and polymorphisms, which could produce different responses regarding reward behavior, impulsivity, and instincts related to food-seeking motivation (Martinez et al. Reference Martinez, Navas-Carretero, Saris and Astrup2014; Qasim et al. Reference Qasim, Turcotte, de Souza, Samaan, Champredon, Dushoff, Speakman and Meyre2018).

In summary, the incentive hope hypothesis may partially explain some of the consequences of economic and nutrition insecurity on excessive food consumption leading to higher obesity rates. However, the economic insecurity hypothesis is less viable for high-income countries and higher-SES groups. Here, the current obesogenic environment and the associated influences on taste preferences, genetic variation, and neurobehavioral factors are likely to play a more prominent role.