Do "healthy fat people" really exist?

Obesity has now become a global "epidemic" and a major public health problem
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Obesity and health may seem like contradictory concepts

Does "MHO" really exist? Recently, "Nature Reviews Endocrinology" (Nature Reviews Endocrinology) published an in-depth introduction to some of the current issues related to "MHO", including diagnostic criteria, research status, and related clinical prognosis
.

Screenshot source: Nature Reviews Endocrinology

Limitations of BMI

Limitations of BMI

The paper points out that being overweight or obese is associated with an increased risk of a variety of diseases, such as type 2 diabetes, cardiovascular disease and various cancers
.

In the past, we mainly used BMI to judge whether a person is obese, but as the most commonly used obesity indicator in epidemiology, the application of BMI is facing more and more doubts

First of all, the question of what BMI is or what is the most healthy range is still controversial
.

There is now evidence that extreme wasting (BMI <18.

Second, it is also questionable whether higher BMI populations are necessarily associated with adverse health outcomes
.

A review article published in JAMA by the team of Professor Katherine Flegal of the United States pointed out that compared with a BMI within the normal range, being overweight (BMI: 25-<30) was associated with a significantly lower risk of all-cause mortality, and this in the elderly more pronounced in the crowd

In addition, some studies have pointed out that some obese people without metabolic abnormalities (such as hypertension, dyslipidemia, and insulin resistance), that is, MHO people, do not need to give priority to weight management.

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Healthy or unhealthy? Contradictory clinical outcomes of MHO

Healthy or unhealthy? Contradictory clinical outcomes of MHO

Do "healthy fat people" really exist? A prospective cohort study published in Diabetologia in 2021, based on an analysis of data from 381,363 subjects (from the UK Biobank), showed that the MHO population had multiple clinical outcomes, including type 2 diabetes, cardiovascular disease, cardiac The risk of occurrence of aging and respiratory diseases is increasing
.

Based on this finding, the researchers questioned: MHO is not necessarily healthy, and MHO, a low-risk group for a specific disease, may not really exist

The paper pointed out that the conflicting clinical outcomes of MHO may be related to the lack of a unified definition of MHO
.

In the aforementioned UK Biobank analysis, MHO was defined as at least 4 of the 6 risk markers included in the study (blood pressure, C-reactive protein, triglycerides, LDL-C, HDL-C, and HbA1c).

Based on the inclusion criteria, the MHO group itself showed residual differences in cardiovascular disease risk factors compared with the control group (in which healthy as well as non-obese people were included)
.

For example, blood pressure levels in the MHO group were slightly higher than those in the control group despite additional antihypertensive medication, and blood levels of C-reactive protein (a marker of inflammation) were also higher than in the control group; in addition, MHO The group also showed slight changes in blood lipid profile with additional lipid-lowering drugs, and the HbA1c level was also slightly higher than that in the control group
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Therefore, although the risk profile of cardiovascular disease in the MHO population did not show important changes compared with the control group, the coexistence of subtle changes in these different risk factors, when added together, may also lead to an increased risk of type 2 diabetes or cardiovascular disease
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In other words, the subjects included in this study did not themselves belong to the truly "metabolically healthy" population

In the future, it is necessary to explore whether the risk of adverse health outcomes is increased in the strictly MHO (ie, normal levels of all 6 markers) population compared with the control group
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These factors may make obese people 'healthier'

These factors may make obese people 'healthier'

The authors of the paper stress that, in addition to the poorly defined and understudied MHO, quantifying the true association between obesity (based on a rough estimate of BMI) and health presents its own challenges
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For example, we still lack reasonable controls for key confounding factors (including regional obesity, physical activity/fitness level, diet quality, etc.
) to exclude these factors from confounding study results
.

In particular, the results of many imaging studies (CT- or MRI-based) over the past three decades have shown that there are significant differences in the accumulation of adipose tissue in different individuals
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in particular:

At the same BMI, people with subcutaneous obesity have a much lower risk of adverse clinical outcomes (such as type 2 diabetes and cardiovascular disease) than people with visceral obesity;

The selective accumulation of fat in the gluteal and femoral regions (more common in premenopausal women) may prevent the development of type 2 diabetes and cardiovascular disease
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In addition to the prognostic value of differences in the location of fat accumulation, different individuals with the same BMI, their behavioral performance and corresponding outcomes are also important mediators of health risk
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For example, at the same BMI, people with a higher overall diet quality and obese people with higher levels of physical activity have significantly lower morbidity and mortality risks from related diseases
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In addition, differences in cardiorespiratory tolerance (a physiological indicator of people who regularly participate in moderate- or high-intensity physical activity) also have a significant impact on individual health risks

Summary: "Healthy Fat People" Exist But Overrated

Summary: "Healthy Fat People" Exist But Overrated

The paper pointed out that for a person with a small waist circumference (low abdominal fat level), a large hip circumference (selective accumulation of fat in the buttocks and femurs), a high-quality diet, daily walking and exercise, and good cardiorespiratory tolerance (relative to the same age and sex The population is moderate.
A premenopausal woman who may be diagnosed as overweight or obese may not actually have a "weight problem"
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From a purely metabolic standpoint, this woman is not only healthy, but super healthy
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The authors of the paper emphasize that the MHO population should be real, but the proportion of this population may be overestimated
.
Due to the lack of clear definition criteria for MHO, many previous studies included too many substandard study populations on the basis of overestimating the prevalence of MHO, and produced misleading conclusions that MHO might bring about the risk of adverse health outcomes
.

References

[1] Després, JP.
Taking a closer look at metabolically healthy obesity.
Nat Rev Endocrinol (2021).
https://doi.
org/10.
1038/s41574-021-00619-6

[2] Flegal, Katherine M.
, et al.
"Association of all-cause mortality with overweight and obesity using standard body mass index categories: a systematic review and meta-analysis.
" Jama 309.
1 (2013): 71-82.