Obesity is characterized by excessive fat accumulation in adipose tissue, and its origin is multifactorial. The excessive intake of carbohydrates and lipids is a determinant for fat accumulation in the adipose tissue, which disrupts the adipocyte function. It has been shown that the overload of lipids in the adipocytes generates proinflammatory and oxidative responses, which, systemically, lead to insulin resistance and other disturbances (Echeverría et al., 2019).

Excessive consumption of high-fat foods, mainly saturated fats and trans fats, significantly contributes to the increase in global obesity rates (Krishnan and Cooper, 2014). Changes in dietary habits, such as reducing fat intake and improving fat quality, are proposed to prevent obesity and metabolic complications (Tutunchi et al., 2020a). In this sense, monounsaturated fatty acids (MUFA) have been pointed out as beneficial for managing and preventing obesity (Yang et al., 2017; Tutunchi et al., 2020b). Oleic acid (OA), which is the most common MUFA in diet, is found in several vegetable oils (olive oil, high-oleic varieties of soybean and canola oil), nuts, and animal products (lard, ground beef, pork, and eggs), being olive oil one of the most OA rich-food (Raatz et al., 2018). OA-rich diets can be involved in regulating food intake, body mass, and energy expenditure by stimulating AMP-activated protein kinase (AMPK) signaling, preventing the nucleotide-binding oligomerization domain-like receptor 3 (NLRP3)/caspase-1 inflammasome pathway, inducing oleoyl ethanolamide (OEA) synthesis, and possibly downregulating stearoyl-CoA desaturase-1 activity (Tutunchi et al., 2020c).

In addition, bioactive components in fruits and vegetables, such as carotenoids, could also contribute to the prevention and treatment of obesity (Coronel et al., 2019). Carotenoids are compounds responsible for the yellow, orange, and red colors in fruits and vegetables (Rodriguez-Amaya, 2019). The anti-obesity action of carotenoids and carotenoid conversion products has been observed in several tissues. In adipose tissue, it seems they affect adipogenesis, metabolic capacity for energy storage and release, oxidation, secretory function, and modulate oxidative stress and inflammatory pathways (Takayanagi et al., 2011; Fenni et al., 2017; Liu et al., 2017; Bonet et al., 2015; Mounien et al., 2019). In the liver, some carotenoids have been shown to reduce oxidative stress, inhibit inflammation, and promote M2 macrophage polarization. They also improve mitochondrial oxidative respiration, and insulin sensitivity and suppress fibrosis (Clugston, 2020; Gao et al., 2021; Lim, 2019).

From a dietary perspective, including MUFA/carotenoid-rich foods in the diet could be an aid in preventing obesity or at least delaying its complications. In this context, pequi oil (PO), which is extracted from Caryocar brasiliense fruit, has high amounts of oleic acid (57.42 g.100g-1) and carotenoids (32.18 mg g−1) (Oliveira et al., 2017), especially β-carotene and β-cryptoxanthin (Azevedo-Meleiro and Rodriguez-Amaya, 2004). Because of that, in the last decade, PO antioxidant (Vale et al., 2019), anti-inflammatory (Junior et al., 2020), antitumor (Miranda-Vilela et al., 2014), antigenotoxic (Colombo et al., 2015), and hypolipidemic (Oliveira et al., 2017; Teixeira et al., 2013) effects have been observed in vitro and in vivo studies. However, to our knowledge, investigation of PO anti-inflammatory and antioxidant effects in diet-induced obesity models is still lacking. Therefore, in this study, we investigated whether PO would have any anti-inflammatory and antioxidant effect on adipose tissue and liver in a diet-induced obesity model. We also wanted to know if those effects would impact insulin resistance and other metabolic disturbances in obese animals. We hypothesized that the partial replacement of lard by PO in a high fat/high sugar diet would improve anti-inflammatory and antioxidant responses in adipose tissue and liver and, accordingly, metabolic disturbances, especially insulin resistance.