This systematic review found that metabolically healthy obese people were associated with all-cause mortality in two studies and CVD mortality in one study. However, studies using metabolically normal, not obese, as the comparison group found no association between metabolically healthy obesity and CVD mortality.

With metabolically healthy normal weight as the reference, the metabolically healthy obese phenotype was associated with a higher risk of cardiovascular events (RR 1.50, 95% CI 1.27 to 1.77; HR 1.60, 95% CI 1.38 to 1.84). However, metabolically healthy obese individuals were not associated with increased risk of all-cause mortality (RR 1.18, 95% CI 0.83 to 1.66; HR 1.07, 95% CI 0.92 to 1.25). The meta-analysis confirms a positive association between metabolically healthy obese phenotype and cardiovascular events, while higher risk for all-cause mortality is not evident.

Compared with healthy participants with normal BMI, metabolically healthy overweight participants had the lowest risk of all-cause mortality (multivariate-adjusted HR 0.926; 95% CI, 0.861-0.997), whereas there was no increased or decreased risk for metabolically healthy obesity (aHR 1.009; 95% CI, 0.886-1.148). In brief, the present study shows that overweight and obesity do not predict increased risk of all-cause mortality in metabolically healthy Chinese individuals.

Although there is no standardized definition of metabolically healthy obesity (MHO), the following criteria have been proposed in addition to the diagnosis of obesity (BMI ≥30 kg/m^2): fasted serum triglycerides ≤1.7 mmol/l (≤150 mg/dl); HDL cholesterol serum concentrations >1.0 mmol/l (>40 mg/dl) in men or >1.3 mmol/l (>50 mg/dl) in women; systolic blood pressure ≤130 mmHg and diastolic blood pressure ≤85 mmHg with no antihypertensive treatment; fasting blood glucose ≤5.6 mmol/l (≤100 mg/dl) and no glucose-lowering drugs.

Despite having excessive body adiposity, these individuals, now defined as "metabolically healthy obesity" (MHO), have a positive metabolic profile characterized by high levels of insulin sensitivity, no hypertension, and good lipid, inflammatory, hormonal, liver enzyme, and immunological profiles. MHO is generally characterized by obesity with absence of metabolic abnormalities such as dyslipidemia, insulin resistance, hypertension, and an unfavorable inflammatory profile.

Despite increased body fat, a subset of people with obesity do not have obesity-related cardiometabolic abnormalities; this is referred to as metabolically healthy obesity (MHO). Individuals with MHO have favorable metabolic profiles and thus relatively lower risk for adverse cardiovascular consequences of obesity compared with individuals with metabolically unhealthy obesity. In the 2015-2018 cycles, an estimated 81.1 million US adults had metabolically unhealthy obesity and 15.6 million had metabolically healthy obesity.

A review protocol summarizing prior meta-analyses states that compared with metabolically healthy normal-weight participants, those with metabolically healthy obesity were at higher risk of cardiovascular events but not all-cause mortality.

The metabolically healthy obese (MHO) phenotype refers to obese individuals with a favourable metabolic profile. Depending on the definition used for metabolic status, a total of 10–40% of obese individuals have the MHO phenotype with a good metabolic profile characterized by high levels of insulin sensitivity, low prevalence of hypertension, and a favourable fasting glucose, lipid, and inflammation profile.

This systematic review and meta-analysis found that metabolically healthy overweight people had a similar risk of death or cardiovascular events to people of normal weight (RR 1.10, 95% CI 0.90 to 1.24; seven studies; I²=0). It concluded that overweight people without metabolic syndrome were not clearly at increased long-term risk in this analysis.

Compared with metabolically healthy normal-weight individuals, obese persons were at increased risk for adverse long-term outcomes even in the absence of metabolic abnormalities. Metabolically healthy obese individuals had increased risk for events when only studies with 10 or more years of follow-up were considered (RR 1.24; 95% CI 1.02 to 1.55).

In most studies, MHO was defined as having ≤2 of the following five metabolic syndrome components: high systolic and diastolic blood pressures, high plasma triglyceride concentration, low HDL-cholesterol concentration, high fasting blood glucose, and a large waist circumference; or ≤1 abnormal component excluding waist circumference. We propose a set of robust criteria to identify people with MHO based on (a) the absence of cardiometabolic diseases, (b) a healthy cardiometabolic blood profile, (c) normal blood pressure, (d) normal intrahepatic triglyceride content, and (e) normal insulin sensitivity.

Broadly, this categorization is described as an absence of metabolic disorders such as insulin resistance, type 2 diabetes, dyslipidemia and hypertension in those patients with BMIs greater than 30 kg/m^2. Metabolically healthy obesity (MHO) is characterized by obese individuals who do not display the typical metabolic disturbances usually associated with obesity.

Metabolically healthy obesity (MHO) is a new term that refers to a subgroup of individuals who are obese (BMI ≥ 30 kg/m²) but do not meet metabolic syndrome criteria. However, there is currently no consensus on the precise definition of MHO. In the majority of studies, MHO is described as obese individuals who have two or more of the metabolic syndrome criteria, including hypertension, high plasma triglycerides, low plasma HDL, high fast blood sugar, and a large waist circumference. The prevalence of MHO was 6.42% at the national level according to the AHA-NHLBI definition, and 23.29% of obese women and 24.55% of obese men were classified as MHOs.

Cardiovascular disease risk was increased in metabolically healthy groups with overweight (RR 1.34, CI 1.23-1.46) and obesity (RR 1.58, CI 1.34-1.85) compared with metabolically healthy normal weight. Cardiovascular disease risk remained increased even when there were no metabolic risk factors used to define metabolic health.

Although there is no clear definition, normal glucose and lipid metabolism parameters—in addition to the absence of hypertension—usually serve as criteria to diagnose MHO. With an age- and gender-dependent prevalence between ~10% to 30%, MHO is not a rare condition. A recent meta-analysis from 12 cohort and 7 intervention studies found a 35% prevalence of MHO with significant regional differences. Great regional and gender-related variations in MHO prevalence have been found, with an age-standardized prevalence of MHO at ~12% across all cohorts.

The concept of metabolically healthy obesity (MHO) implies that a subgroup of obese individuals may be free of the cardio-metabolic risk factors that commonly accompany obese subjects with adipose tissue dysfunction and insulin resistance, known as having metabolic syndrome or the metabolically unhealthy obesity (MUO) phenotype.

Numerous studies have demonstrated that people with metabolically healthy obesity have a lower risk of mortality and other comorbidities than those with metabolically unhealthy obesity and are not at a higher risk than people who are normal weight. The article also reports that the risk of cardiovascular events was greater in the metabolically healthy obesity group than in the metabolically healthy non-obese group (HR 1.14; 95% CI 1.05-1.24).

Accordingly, an overweight or obese subject was classified as metabolically healthy overweight/obesity (MHOv/O) if he or she had one or none of the following: triglycerides ≥1.7 mmol/L; systolic blood pressure ≥130 mm Hg; diastolic blood pressure ≥85 mm Hg; fasting blood glucose ≥5.6 mmol/L; and HDL-cholesterol <1.04 mmol/L for men and <1.29 mmol/L for women. Using these criteria, a subset of overweight and obese individuals were identified as metabolically healthy.

In the overall population, the prevalence of the MHO phenotype was 8.6%. Among obese individuals, a phenotype of patients who do not present metabolic abnormalities, the so-called metabolically healthy obese (MHO) phenotype, has been described. The prevalence of the MHO phenotype varies greatly across studies (2.2–11.9% of the general population and 6–40% of the obese population), depending on the study design and, particularly, on the criteria used for its definition. The prevalence of a metabolically healthy status was 87.1% for the overweight individuals and 55.1% for obese individuals.

There are many persons with metabolically healthy obesity (MHO). It has been reported that 18–44% of overweight or obese persons are metabolically healthy, with high insulin sensitivity and no diabetes, dyslipidemia, or hypertension. In the present study, MHO accounted for 14% of all subjects and 39% of obese persons. Goday et al. reported that metabolically healthy people can be classified as overweight (87.1% of cases) and obese (55.1% of cases).

Metabolically healthy obesity (MHO), as it will be referred to in this review, has been previously defined as a subgroup of obese individuals who do not have insulin resistance, lipid disorders, or hypertension. Five studies defined 'metabolically healthy' as absence of MetS with study specific modifications to the MetS criteria.

In general, healthy obesity indicates the absence of metabolic disorders, including type 2 diabetes, dyslipidemia, and hypertension, in an obese individual. Metabolically healthy obesity (MHO) is characterized by the absence of metabolic abnormalities such as dyslipidemia, insulin resistance, hypertension, and an unfavorable inflammatory profile.

The prevalence of MHO and MONW was 7.27% and 19.98%, respectively. The reported prevalence of MHO ranges from 2.2 to 11.9% in the general population and from 6 to 40% among obese persons. These proportions vary widely due to different definitions and criteria used to define metabolically healthy obesity.

Metabolically healthy normal weight (MHN): BMI <30 kg/m^2 without metabolic syndrome (MetS). Metabolically unhealthy normal weight (MUN): BMI <30 kg/m^2 with MetS. Metabolically healthy obesity (MHO): BMI ≥30 kg/m^2 without MetS. Thus the MHO category comprises individuals with obesity who do not meet criteria for metabolic syndrome.

Among normal weight and overweight subjects, the prevalence of metabolically healthy individuals was similar between BMI and percent body fat (77.6 vs. 75.7% and 58.8 vs. 62.5%, respectively); however, there was a pronounced difference among obese subjects (34.0 vs. 47.7%). Our findings indicate that approximately one-half of obese people are metabolically healthy when classified using percent body fat criteria, which is significantly higher than previously reported using BMI.

Metabolically healthy obese were prevalent in 8.2% of the baseline population and 28.5% of the obese subjects. The concept of metabolically healthy obese refers to obese individuals who do not exhibit the typical obesity-related metabolic abnormalities such as insulin resistance, dyslipidemia, or hypertension.

The prevalence of MHO ranged between 6% and 75%. This wide range reflects that different studies use different criteria to define metabolically healthy obesity and sample different populations. Overall, MHO refers to individuals with obesity who lack cardiometabolic risk factor clustering.

Obesity phenotypes have been observed in which a subset of obese persons may be considered as having metabolically healthy obesity (MHO) with no evidence of existing cardiometabolic disease. The present study found that MHO was best defined by the following criteria: (1) systolic blood pressure less than 130 mm Hg and no use of blood pressure-lowering medication, (2) waist-to-hip ratio less than 0.95 for women and less than 1.03 for men, and (3) no prevalent type 2 diabetes.

At present, a set of universally accepted defining criteria for metabolically healthy obesity has not been established. Most experts agree that metabolically healthy obesity is typically marked by the absence of any metabolic and cardiovascular disease, including type 2 diabetes, dyslipidemia, hypertension, and atherosclerotic cardiovascular disease in a person with obesity. One set of practical criteria for metabolically healthy obesity that has been proposed for adults includes a diagnosis of obesity (BMI ≥30 kg/m^2) AND demonstration of normal triglycerides, HDL-cholesterol, blood pressure, and fasting blood glucose without use of cardiometabolic medications.

Among obese (BMI ≥30 kg/m²) participants, prevalence of MHO ranged between 3.3 and 32.1% in men and between 11.4 and 43.3% in women according to the criteria used. Using percent body fat led to a prevalence of MHO ranging between 6.4 and 43.1% (men) and 12.0 and 55.5% (women). These data show that a substantial subset of obese individuals can be considered metabolically healthy depending on the definition applied.

Metabolically healthy obesity (MHO) is a new concept in which an individual may exhibit an obese phenotype in the absence of any metabolic abnormalities. Approximately 30% of obese individuals do not have metabolic syndrome and are thus at a lower risk of developing type 2 diabetes and cardiovascular disease.

Metabolically healthy obesity (MHO) refers to a body mass index (BMI) above 30, but preserved metabolic health. There are no universal criteria to identify MHO, but metabolic health is often defined as the absence of metabolic syndrome. In this study, metabolic health was defined as having ≤1 of the following: hypertension, hyperglycemia or type 2 diabetes, hypertriglyceridemia, and low HDL-cholesterol, based on NCEP ATP-III criteria for metabolic syndrome.

Prospective analyses of obesity phenotypes and incident cardiovascular disease showed that compared with metabolically healthy normal-weight adults, metabolically healthy obese adults were more likely to have incident cardiovascular disease (HR 1.38, 95% CI 1.15-1.67).

In a meta-analysis of prospective cohort studies, metabolically healthy overweight/obesity was associated with increased risk of cardiovascular disease in adults, even in the absence of metabolic risk factors. The review also notes that some studies found all-cause mortality to be comparable or lower in metabolically healthy overweight individuals than in metabolically healthy normal-weight individuals.

They identified several characteristics of metabolically healthy obesity. These include a high BMI with a waist size of no more than 40 inches for a man or 35 inches for a woman, normal blood pressure, cholesterol, and blood sugar, normal sensitivity to insulin, and good physical fitness. Thus some people who are overweight or obese can be free of metabolic syndrome components and have normal insulin sensitivity.

Metabolically healthy obesity is defined as having a BMI over 30 without the presence of metabolic syndrome factors such as high blood pressure, cardiovascular disease, type 2 diabetes, and high cholesterol. A person with metabolically healthy obesity has a body mass index (BMI) of over 30, but they do not have metabolic syndrome, meaning their blood pressure, blood fats, and blood sugar are within healthy ranges without medication.

Metabolic health is defined as having optimal levels of five factors: blood glucose, triglycerides, high-density lipoprotein cholesterol, blood pressure and waist circumference, without the need for medications. Data revealed that only 12.2 percent of American adults are metabolically healthy, which means that only 27.3 million adults are meeting recommended targets for cardiovascular risk factors management.