Recently, the global overfat pandemic was estimated to encompass between 62 and 76% of the world’s total population (1). This relatively new term, overfat, refers to an accumulation of excess body fat that becomes sufficient to impair health (1). Even more recently, levels of overfat adults and children in developed countries have been shown as being substantially higher than worldwide averages (2). For example, in the US, 86% of adults and 52% of children were estimated to be overfat (2). The data used to calculate these estimates were derived in part from those shown by Ng et al. (3) for estimated overweight and obesity rates in US adults (66%). More recent data published by the Centers for Disease Control and Prevention (CDC) for 2014 show that over 70% of American adults are overweight or obese (4, 5). Determination of these overweight and obese classifications are usually based on measures of body mass index (BMI), with overweight defined with a score of ≥25 to <30 kg/m² and obesity as ≥30 kg/m². However, while BMI can overestimate fat mass in certain populations, including Polynesians, African American, and elite strength athletes, because BMI is not a direct measure of body fat it can misclassify up to 50% or more patients with both increased body fat and its associated disease risk factors (6, 7).

Estimations of overfat adults and children are important for public health reasons. Excess body fat is associated with poor health, and the development of insulin resistance and low-grade systemic chronic inflammation (8, 9). These conditions can lead to various cardiovascular and metabolic (cardiometabolic) impairments such as dyslipidemia, increased blood glucose, and hypertension, raising the risks of chronic diseases such as Type 2 diabetes (10, 11), cardiovascular diseases (12, 13), and most cancers (14). Chronic inflammation has also been linked to neurodegenerative diseases, including the most common cause of dementia, Alzheimer’s disease (15, 16).

The burden of excessive body fat can begin at an early age (17, 18), even in gestation (19), with over 55% of obese children estimated to have nonalcoholic fatty liver disease (20). Children with excess body fat are likely to feed the overfat pandemic and are at increased risk of becoming overfat adults with chronic disease (21–25).

The primary purpose of this review was to build upon previous estimations of overfat prevalence in developed countries by using new data from the CDC to estimate the overfat prevalence in American adults (≥20 years) and children (2–19 years), and to expand the definition of overfat as excess body fat associated with at least one additional risk factor of impaired cardiometabolic or physical health. The secondary goals were to highlight the role of dietary sugar as a potential primary cause of the overfat pandemic and mention new data showing the increased prevalence of exercise that parallels the rising prevalence of overfat to further emphasize the secondary role exercise may play in fat loss.

While overfat was recently defined as excess body fat that impairs health (1), in this article, we offer an expanded, quantitative description in relation to its associated cardiometabolic, physical performance, and other measurable health impairments. Overfat is both an excess amount of body fat, depicted by increased body fat percentage or waist circumference (WC), and cardiovascular, metabolic, or physical impairments caused by being overfat (26). These topics are detailed in this section and throughout this review.

Excess body fat contributes to cardiometabolic impairments, resulting in various downstream conditions such as chronic inflammation and insulin resistance, risk factors such as abnormal blood glucose, cholesterol, triglycerides, and blood pressure, and chronic diseases, including Type 2 diabetes, cardiovascular disease, cancer, and Alzheimer’s disease (1). Increased body fat mass also raises the risk of mortality (27–29) and shares direct links to gallbladder disease, gout, pulmonary diseases, and sleep apnea (30), while the absence of excess body fatness lowers the risk of most cancers (14).

Physical performance impairments associated with excess adiposity include musculoskeletal disorders, such as lower-back and other pain syndromes, reduced work productivity in forms such as absenteeism and disability, as well as lower quality of life (31), and include locomotive disorders such as knee and hip osteoarthritis, lumbar spondylosis, and osteoporosis (32). Performance was also assessed in normal-weight obese children aged 3–6 years, who showed significantly worse levels of fundamental motor skills compared to their normal-weight non-obese counterparts (33). As fundamental motor skills in early life play a crucial role in physical, cognitive, and social development (34), childhood adiposity may indirectly exacerbate physical performance impairments into adulthood.

As BMI often misclassifies body fatness, reductions of misclassification rates can be improved using dual energy X-ray absorptiometry (DXA) to directly measure body fat percentage (35). DXA is one of the most accurate and precise methods of assessing adiposity (36). While there is no consensus on how to define excess body fat percentage (37), Lohman’s criteria of suggested cutoffs >17.6% for males and >31.6% for females is widely accepted in body composition research (38–41). However, measurable health impairments associated with ≥2 cardiometabolic abnormalities were found at DXA-derived body fat levels >15.3% in men and >29.8% in women (42). DXA-derived body fat levels from the 1999 to 2004 National Health and Nutrition Examination Survey (NHANES) using Lohman’s criteria is shown in Figure 1, which shows mean body fat for men was 28%, with the cutoff of 17.6% representing approximately the 5th percentile (17.4%), and in women, mean body fat was 39.9%, with 31.6% between the 10th and 15th percentile (43).

The overfat condition can also be evaluated indirectly using waist measures, which, like BMI, do not directly estimate body fat percentage. Epidemiologic studies have demonstrated that increased abdominal fat, assessed through WC and waist-to-height ratio (WHtR), can predict adiposity-related risk (37). WHtR was more strongly related to cardiometabolic risk factors than BMI (29, 44). In normal-weight non-obese children with a commonly used cutoff of WHtR ≥ 0.5, over 55% had one to three cardiometabolic health risk factors associated with increases in WC, triglycerides, and blood pressure (45). Adults from the NHANES, 1999–2000 cohort showed that 86% of adults with abdominal obesity [defined as WC in men ≥ 102 cm (40″), in women ≥88 cm (35″)] had at least one other cardiometabolic risk factor (46).

Based on these observations, we summarize the definition of overfat as excess adiposity measured accurately (directly, such as by DXA, or indirectly, such as by WHtR) combined with at least one additional measurable risk factor of impaired cardiometabolic or physical health.

We have previously described overfat as a condition of excess body fat with two subcategories that include: (1) those who are overweight and/or obese with excess body fat and (2) normal-weight and non-obese individuals with excess body fat, including those with abdominal obesity and sarcopenic obesity (1, 2). Collectively, both subcategories are prevalent in adults and children, with the exception of the sarcopenic obesity condition, which is prevalent only in adults. The prevalence of the population who are overweight and obese has been well described in the literature and represents the largest subcategory of the overfat condition in the US and worldwide (1, 2).

To estimate the prevalence of overfat adults and children in the US, we combined the populations of overweight, obese, and normal-weight individuals with increased health risks (MONW). In adults, recent crude data estimated overweight and obese prevalence in the US at 70.7% (5). Metabolically obese normal weight prevalence has been estimated between 5 and 45%, with variations due to ethnicity, sample size effects, differences in MONW definition, social and demographic factors, and others (66, 67). The relatively recent prevalence of MONW adult populations in North America and Europe that included both genders and a wide range of ages have been estimated by various authors to be between 24 and 36% (55, 68–72). However, we feel the meta-analysis by Wang et al., which showed the overall prevalence of MONW adults in the general population worldwide at 20% (95% CI 16.54–23.94), was an appropriate estimate for the US population, and was previously used for estimating overfat prevalence in developed countries (2). Wang et al. (54) included publications between 2006 and 2013 with a wide range of populations including Europeans (individual countries and mixed populations), North Americans (US and Canada), and Asians (including Chinese, Indian, and Korean). Combining the categories of overweight, obese, and MONW US adults brings the prevalence of overfat in the US to 90.7%.

In children, as in adults, a wide range of normal weight high body fat conditions has been found in various populations. Mokha et al. (58) showed that in normal-weight non-obese children with a WHtR ≥ 0.5, over 55% had one to three cardiometabolic health risk factors associated with increases in WC, triglycerides, and blood pressure. In a Caucasian population of high school students, Olafsdottir et al. found 42% were normal-weight obese, defined as normal BMI with DXA body fat >17.6% in males and >31.6% in females, and with one or more risk factors for metabolic syndrome (39). Griffiths et al. (73) showed that 17.6% of normal-weight non-obese boys and 17.3% of normal-weight non-obese girls who exceeded a WHtR of 0.5 were considered “at risk,” as compared with children who were overweight or obese and above the 85th percentile, and Flegal et al. (45) estimated the prevalence of DXA-based adiposity in children with normal BMI below the 85th percentile and found that 35% within the 65th percentile cutoff and 24% within the 70th percentile cutoff had high adiposity. The WHtR-based study of Griffiths et al. (UK children) and the DXA-based data from Flegal et al. (US children) produced an average of 22% of overfat children (both genders), a figure also used in our recent estimates of children in developed countries (2). Combined with recent rates of US overweight and obese children aged 2–19 years of 46.9% (5), we estimated the overfat prevalence of US children to be 68.9%. Figure 3 shows the prevalence of overfat adults and children in the US, with State-by-State rates of overfat, which follow overweight and obese levels, shown in Figure 4.

While the health consequences of being overweight or obese are widely known, it is the specific condition of excess body fat that is associated with various disease risk factors, chronic illness, increased morbidity and mortality, and reduced quality of life. The problems associated with the rise in prevalence of overweight and obese classifications alone have replaced the longstanding problems of undernutrition and infectious diseases (30). Moreover, the overfat pandemic, with its potential downstream conditions, has created a major global economic burden (2). In a single year (2014) in the US, for example, total health-care costs climbed to $3.2 trillion US dollars (75). Overfat-related cardiometablic and physical impairments could be a substantial portion of these annual costs.

In addition to genetic influences, two lifestyle factors, physical activity, and dietary sugar, can play key roles in the development of excess body fat and are reviewed here.

The number of overfat Americans continues to rise, with estimations of 91% in adults and 69% in children, the highest levels in US history. Recognition of the overfat pandemic is a key step in initiating its reversal and prevention. Because overfat prevalence continued rising during periods of increased exercise rates, current public health guidelines to address the overfat pandemic may require more emphasis on food, especially in reducing consumption of excess refined carbohydrates, including added sugars.

PM—originator of ideas, data collection, analysis, critical thinking, and writing of the manuscript. PL—contributed to ideas, critical thinking, and writing of the manuscript.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. PM is an independent clinical consultant, writes articles and books that include the topics presented herein, and has a business website pertaining to health and fitness (www.philmaffetone.com). IR-D works for a health and fitness company. PL is an independent consultant, writes articles and books, and has a website pertaining to performance, health, and longevity (www.plewsandprof.com).