Obesity

Obesity is when a person's weight is higher than the healthy weight range advised by public health bodies, and higher than the overweight range. The CDC regards a Body Mass Index of 30 or higher in adults as obesity. One in 3 people in the United States have obesity.

Obesity is considered a health problem because it has been linked to a number of serious, chronic dieases including heart disease, type 2 diabetes and certain types of cancers.

ME/CFS
Obesity is not considered a trigger or risk factor for ME/CFS, and is not a sign or symptom of ME/CFS. Obesity is a differential diagnosis for ME/CFS and it can cause fatigue; clinicians are advised to consider this along with other symptoms, test results, and a personal history (e.g. whether symptoms began suddenly or any recent weight change).

According to the US ME/CFS Clinician Coalition, obesity is a potential comorbidity in people with ME/CFS, although it is not listed as a common comorbidity in either the Canadian Consensus Criteria or the International Consensus Criteria.

Weight changes in ME/CFS
Medications taken for some ME/CFS symptoms can increase weight, particularly:
 * amitriptyline and other tricyclic antidepressants, which are often used for pain, especially in Fibromyalgia, or for sleep dysfunction
 * quetiapine, which may be used off-label for sleep problems
 * Lyrica (pregabelin) which is commonly used for pain

Marked weight loss or weight gain can also be a result of the neuroendocrine symptoms in some people with ME/CFS, or result from changed behaviors caused by reactive depression, which is relatively common in ME/CFS.

Exercise
The exercise intolerance caused by ME/CFS means that many patients are unable to do as much physical activity as they would like to. Physical activity and a healthy, balanced diet are the main ways to prevent and reduce obesity.

Severe obesity
The CDC's Fukuda criteria for chronic fatigue syndrome (1994), which was retired in 2017, did exclude patients with severe obesity, which they defined as a BMI of 45 or greater, from a diagnosis of ME/CFS. Understanding of ME/CFS has changed considerably and it is no longer regarded as primarily a "fatigue" illness, but as a complex multi-systemic neurological disease, with post-exertional malaise rather than chronic fatigue as the hallmark symptom.

The CDC does not suggest obesity as a differential diagnosis for ME/CFS and does not list it as a common comorbidity. The phyiscal examination suggestions do not refer to weight or BMI values, although they may be assessed as part of routine practice or in identifying other existing conditions.

Treatment
Treating obesity does not cure ME/CFS, and clinical trials for different ME/CFS treatments typically have patients in the healthy weight range. Weight loss in ME/CFS patients with obesity has not been a major focus of clinical practice or research, although clinicians are advised to address all comorbidities found.

Notable articles

 * 2007, Body mass index and fatigue severity in chronic fatigue syndrome (Full text)
 * In women, there was no relationship between BMI and vitality subscale or global fatigue index scores (P = 0.99 and P = 0.44). For men, vitality subscale scores significantly decreased as BMI increased (P = 0.02).
 * Conclusions: In CFS patients, the prevalence of obesity was low despite risk factors for weight gain. Fatigue severity and BMI were unrelated in women with CFS, but this relationship may differ for men.


 * 2013, Examining the impact of obesity on individuals with chronic fatigue syndrome (Abstract)
 * 2017, Obesity in adolescents with chronic fatigue syndrome: an observational study (Full text)
 * Adolescents who had attended specialist CFS/ME services had a higher prevalence of obesity (age 13 years: 9.28%; age 16 years: 16.43%) compared with both adolescents classified as CFS/ME in ALSPAC (age 13 years: 3.72%; age 16 years: 5.46%) and those non-CFS in ALSPAC (age 13 years: 4.18%; age 16 years: 4.46%).

Learn more

 * Defining Adult Obesity - CDC