Obesity, considered as the epidemic of the XXI century, is a multifactorial and complex disease of which worldwide prevalence is still increasing in spite of the fact that some of the best groups of researchers started studying it more than half a century ago.

This pathological condition consists of an excessive fat accumulation together with a mild chronic inflammation. This accompanying proinflammatory status is considered the link between obesity and the development of its related comorbidities such as insulin resistance and type 2 diabetes, cardiovascular diseases, cancer, and nonalcoholic fatty liver disease.

In this sense, gathering the new advances in cells, animals or, preferentially, humans and trying to shed some light to further understand the molecular mechanisms involved in the initiation and maintenance of the inflammatory process are of great value for the scientific community. The main triggers have been considered hypoxia, oxidative stress, and endoplasmic reticulum stress, but this special issue seeks to find new information about these factors and would also welcome comprehensive reviews about one or several factors.

Potential topics include but are not limited to the following:

• Metabolic imprinting
• Browning and beiging processes
• Regional and quantity of fat accumulation
• Nutrigenetics and Nutrigenomics
• Oxygen tension: including hypoxia and hyperoxia
• Endoplasmic reticulum stress
• Reactive oxygen species overproduction (oxidative stress) and antioxidants
• Endocrine or immune control: hormones and adipokines, myokines, cytokines, and others
• Macrophage infiltration and M1/M2 phenotype polarization
• Omega 3, lipid mediators, and other fatty acids
• Chrononutrition