Balancing act: rheumatoid arthritis, inflammation, and energy.

RA & Weight Loss: Unlocking the Link Between Inflammation and Energy Expenditure

Reese Marlowe in Health & Wellness August 2025 • 5 min read.

"Is rheumatoid arthritis affecting your weight? Discover how inflammation impacts metabolism and what you can do about it."

Weight fluctuations can be particularly frustrating and confusing. If you're one of the many individuals living with rheumatoid arthritis (RA), you might have noticed a connection between your RA symptoms and changes in your weight. For years, medical professionals have observed that individuals with rheumatoid arthritis (RA) often experience weight loss, recognizing it as an early indicator of the disease.

But what exactly is the connection between RA and changes in body weight? Recent studies indicate that many RA patients experience a moderate degree of cachexia, a metabolic syndrome characterized by muscle wasting. The underlying mechanisms, similar to those associated with cancer or infection, are still not fully understood. Researchers are working hard to unravel the reasons behind this phenomenon.

A study published in the 'Journal of Inflammation Research' delves into this complex relationship, seeking to determine whether rheumatoid cachexia is primarily due to reduced food intake, increased metabolism, or an inflammatory cytokine response. By examining patients during periods of both relapse and remission, the researchers shed light on how disease activity impacts body composition and energy expenditure. Understanding these dynamics is crucial for developing effective strategies to manage weight and improve overall health in individuals with RA.

How Does Inflammation Affect Energy Expenditure in RA?

Balancing act: rheumatoid arthritis, inflammation, and energy.

The study published in the Journal of Inflammation Research, involved sixteen patients admitted to a hospital because of an RA flare-up. Researchers assessed these patients clinically to determine their disease activity, and then re-examined them six weeks later. During these assessments, scientists measured several factors, including fat-free mass (FFM), dietary intake, resting energy expenditure (REE), and plasma concentrations of interleukin-6 (IL-6).

The goal was to understand how these factors changed with the ebb and flow of inflammation and RA disease activity. The data collected from the RA patients was carefully compared with that of sixteen healthy control subjects who were matched for age and sex. This comparison helped the researchers isolate the specific effects of RA on the patients' bodies and energy balance. Here's a breakdown of what the researchers measured and why:

Fat-Free Mass (FFM): This measures the amount of lean tissue in the body, including muscle and bone. It’s an important indicator of overall health and metabolic function.
Dietary Intake: This assesses how much food and nutrients the patients consumed. It helps determine whether changes in body composition are related to changes in diet.
Resting Energy Expenditure (REE): This measures the amount of energy the body uses while at rest. It indicates how efficiently the body is functioning and whether metabolism is altered by RA.
Plasma Concentrations of Interleukin-6 (IL-6): IL-6 is an inflammatory cytokine, a type of protein that signals the immune system. Measuring its concentration helps understand the role of inflammation in RA-related cachexia.

The study's results revealed significant insights. At the beginning of the study, patients with RA had lower body weight, body mass index (BMI), and FFM compared to the control group. However, after six weeks, as the patients' disease activity decreased, their FFM was no longer statistically different from that of the controls. Interestingly, there were no significant differences in food intake between the patients and controls, or between the patients at the two different time points. Despite this, the resting energy expenditure (REE) was higher in patients, especially when corrected for FFM. The plasma IL-6 concentrations were also significantly higher in patients than in controls, suggesting a link between inflammation and energy expenditure.

Practical Implications and Future Directions

These findings suggest that the reduced FFM in RA patients is not due to reduced food intake. Instead, energy expenditure is greater in patients, particularly during acute flares of disease activity. While IL-6 is not the only factor involved, increased production of IL-6 may contribute to increasing REE. More research is needed to fully understand the mechanisms driving these changes and to develop targeted interventions to manage weight and improve overall health in individuals with RA.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.2147/jir.s16508, Alternate LINK

Title: The Effect Of Disease Activity On Body Composition And Resting Energy Expenditure In Patients With Rheumatoid Arthritis

Subject: Immunology

Journal: Journal of Inflammation Research

Publisher: Informa UK Limited

Authors: Khalid Binymin, A L Herrick, G L Carlson, Stephen Hopkins

Published: 2011-05-01

Everything You Need To Know

How does rheumatoid arthritis (RA) affect a person's weight?

Rheumatoid arthritis (RA) can affect weight through a complex interplay of factors. Individuals with RA often experience weight fluctuations. This can include both weight loss, sometimes observed as an early indicator of the disease, and potentially weight gain. The connection involves the inflammatory processes associated with RA, which can influence metabolism and energy expenditure.

What is rheumatoid cachexia and how does it relate to RA?

Cachexia, a metabolic syndrome marked by muscle wasting, is seen in many individuals with rheumatoid arthritis (RA). The exact mechanisms causing this are still being investigated, but researchers are exploring if it's related to reduced food intake, increased metabolism, or the inflammatory cytokine response. The study also observed that RA patients experienced a higher resting energy expenditure (REE), especially when corrected for fat-free mass (FFM). This suggests that RA impacts how the body uses energy, potentially leading to weight changes.

What factors were examined in the study to understand the effects of RA on the body?

The study investigated how disease activity impacts body composition and energy expenditure by comparing RA patients during flare-ups and remission with healthy controls. Researchers measured fat-free mass (FFM), dietary intake, resting energy expenditure (REE), and plasma concentrations of interleukin-6 (IL-6). These measurements helped determine how RA influences metabolism and energy balance. The study found that the reduced fat-free mass (FFM) in RA patients isn't related to reduced food intake. Instead, energy expenditure is increased, particularly during periods of high disease activity.

What is Interleukin-6 (IL-6) and what role does it play in RA?

Interleukin-6 (IL-6) is a type of inflammatory cytokine, a protein that signals the immune system. Measuring its concentration helps understand the role of inflammation in RA-related cachexia. The study observed that plasma IL-6 concentrations were significantly higher in patients with rheumatoid arthritis (RA) than in the control group, suggesting a link between inflammation and energy expenditure. This suggests that inflammation, as indicated by high IL-6 levels, may contribute to the increased resting energy expenditure (REE) seen in those with RA.

Why is it important to understand the connection between rheumatoid arthritis, inflammation, and weight changes?

Understanding the link between rheumatoid arthritis (RA), inflammation, and weight changes is crucial for developing effective strategies to manage weight and improve overall health in individuals with RA. The findings suggest that reduced fat-free mass (FFM) in RA patients is not due to reduced food intake, but rather increased energy expenditure. Further research is needed to fully understand these mechanisms and develop targeted interventions to manage weight and improve overall health.