Adiposity / Obesity

Overweight / obesity has a positive energy imbalance and means excessive nutrients intake, accumulation of excess body fat. The BMI is ≥ 25 for overweight, and ≥ 30 for obesity (36, 37).

Adiposity/Obesity is a global pandemic. Over 50% of the global population is overweight and it is recognized across the life span. In 2016, approximately 650 million people were considered obese. By 2030, obesity is projected to affect 1.12 billion people. Therefore, it is a significant global health and socio-economic issue.Obesity increase is mainly due to:

* Easy and long-term access to energy-dense foods 
* Sedentary lifestyle (1, 2, 3, 4, 5, 6, 7)

In adiposity/obesity, the energy extracted from food consumed is greater than the energy used by the body. All calories can contribute to a positive energy balance and fat gain (8, 9).

Adiposity/obesity results in an increased body mass index (BMI) with consequent weight gain and other comorbidities (10, 11, 12). BMI is calculated as weight divided by the square of height (kg/m²). Its increase is associated with enhanced insulin resistance, is linked to higher levels of low-density lipoprotein-cholesterol (LDL-C) and higher levels of triglycerides (12).

Overeating is linked to altered central nervous system (CNS) reward and satiety responses to food. Similar CNS reward and satiety responses are observed in drug addiction (13, 14, 15, 16, 17, 18).

The rise in obesity contributes to a higher incidence of obesity-related diseases (comorbidities) contributing to increased mortality rates and healthcare costs. They include

[Type 2 diabetes (T2D)](?id=faf94820-8bfe-426c-8850-c758558c19cb&linkText=Type+2+Diabetes)
[Cardiometabolic disease (CMD)](brain://jBV7m7FQg0aiOc347k2n7A/CardiometabolicDiseaseCmd)
[Cardiovascular disease](brain://qszQuKPeYEGRBDs2LPGDRw/CardiovascularDiseasesCvd)
[Chronic kidney disease](brain://tBJMP6bc20aI9hUWo5XZQg/ChronicRenalFailureChronicKidneyDiseaseCkd),
[Liver disease](brain://aSVKJ1n-F0ywo80CcdCThg/HepaticDiseaseLiverDisease)
[Metabolic syndrome (MetS)](brain://t4m1Aug7GEqQe-m4dJEdeQ/AdiposityObesityMetabolicSyndromeMetS) / [Insulin resistance](?id=f4b5a071-6955-4d07-85de-050ef64510a6&linkText=insulin+resistance)
[Non-alcoholic fatty liver disease](?id=94f8f4d3-a5ac-403f-ac5e-476c6384a22f&linkText=nonalcoholic+fatty+liver+disease)
[Type 2 diabetes (T2D)](?id=faf94820-8bfe-426c-8850-c758558c19cb&linkText=Type+2+Diabetes)

It also affects non-metabolic diseases, increasing susceptibility to infections and cancer, too. It also reduces life expectancy and quality of life (5, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31).

Obesity poses a risk for Atherosclerosis / Coronary Artery Disease (CAD) / Coronary Heart Disease (CHD) / Ischemic Heart Disease (IHD), hypertension, myocardial infarction, stroke, insulin resistance (IR), Type 2 Diabetes (T2D), dyslipidemia, nonalcoholic fatty liver disease, and other diseases. Weight loss improves these metabolic complications (32, 33).

Also, Childhood obesity is at epidemic levels and a major public health concern. It is associated with metabolic syndrome and linked to non-alcoholic fatty liver disease (NAFLD) (34).

Accordingly, the probability of regaining average body weight after reaching an obese state is less than 1% (35).

References

(1) Jebb & Moore 1999 Med. Sci. Sports Exerc. 31(11 Suppl.): S534–S541
(2) Hu 2003 Lipids 38: 103-108
(3) Kelly et al. 2008 Int J Obes (Lond). 32(9): 1431-1437
(4) Cerdó et al. 2019
(5) Jastreboff et al. 2019 Obesity (Silver Spring) 27(1): 7-9
(6) Larik et al. 2024 Cell Host & Microbe 32(8): 1225
(7) Młynarska et al. 2025 Curr Issues Mol Biol 47: 787
(8) Stanhope et al. 2018
(9) Boscaini et al. 2022 Molecular Metabolism 57: 101427
(10) Sam & Mazzone 2014 Translational Research 164: 284-292
(11) Blüher 2019 Nature Reviews Endocrinology 15: 288-298
(12) Duan et al. 2021 PLoS ONE 16(8): e0255446
(13) Trinko et al. 2007 Physiol Behav. 91(5): 499-505
(14) Volkow et al. 2008 NeuroImage. 42(4): 1537-1543
(15) Rothemund et al. 2007 Neuroimage 37(2):410-421
(16) Ten Kulve et al. 2015 Diabetologia 58(12):2688-2698
(17) Van Bloemendaal et al. 2015 Diabetes Obesity Metab. 17(9): 878-886
(18) Ten Kulve et al. 2016 Diabetes Care 39(2):214-221
(19) Berg & Scherer 2005 Circ Res 96: 939-949
(20) Kanda et al. 2006 J Clin Invest 116: 1494-1505
(21) Lusis et al. 2008 Nat. Rev. Genet. 9: 819-830
(22) Braunet al. 2011 Int. J. Biol. Sci. 7: 1003-1015
(23) Scully 2014 Nature 508: S50
(24) Morris 2015 Mol Endocrinol 29: 946-962
(25) Rhee et al. 2016 Curr Opin Nephrol Hypertens 25: 208-216
(26) Abdelaal et al. 2017 Ann Transl Med. 5(7): 161
(27) Doerstling et al. 2017 Front Oncol 7: 216
(28) Tenorio-Jiménez et al. 2018
(29) Pugliese et al. 2022 Int J Obes (Lond) 46: 449-465
(30) Yang et al. 2022 Healthcare 10: 1616
(31) World Health Organization 2020 https://www.who.int/news-room/ fact-sheets/detail/obesity-and-overweight
(32) Goodpaster et al. 1999 Diabetes 48(4): 839-847
(33) Vidal 2002 Int J Obes Relat Metab Disord. 26(Suppl 4): S25-S28.
(34) Carbajo-Pescador et al. 2019 Dis Model Mech 12: doi: 10.1242/dmm.039206.
(35) Fildes et al. 2015 Am J Public Health 105(9): e54
(36) World Health Organization (WHO). Malnutrition. 2023.
(37) Kiani et al. 2022 J Prev Med Hyg 63(Suppl_3): E93-E101

see also:
Adiposity / Obesity & Cancer / Tumors
Adiposity / Obesity & Incidence / Prevalence
Adiposity / Obesity & Lifestyle / Lifestyle Changes
Consequences & Adiposity / Obesity
Metabolic Syndrome (MetS)
White Adipose Tissue (WAT)