Rheumatoid arthritis (RA) is a chronic, progressive condition affecting the joints. Symptoms worsen during flare-ups and may disappear during periods of remission. The disease is systemic, meaning it affects areas beyond the joints. According to the Centers for Disease Control and Prevention (CDC), more than 58 million Americans have been diagnosed with some form of arthritis. With over 100 forms of the disease, arthritis has an enormous impact on its sufferers, particularly when it affects important weight-bearing joints like the knees and hips. While obesity is a known risk factor for RA, the relationship between RA and weight is complex. Some individuals with RA experience weight loss, while others gain weight. This article explores the reasons behind weight loss in RA, the potential risks associated with it, and strategies for maintaining a healthy weight.
The Link Between Obesity and Rheumatoid Arthritis
Obesity and being overweight are known risk factors for rheumatoid arthritis. A reported 39 million people suffering from arthritis are overweight or obese, and the benefits of weight loss can make a tremendous difference. Because body movement creates shifting balances and changes in your center of gravity, an additional 5 pounds of weight can add 25 pounds of force to joints. Losing 10 pounds can reduce the progression of cartilage loss in osteoarthritis by 50% if you’re overweight, which is another encouraging statistic.
Fat isn’t inert. It’s active tissue that generates substances that encourage inflammation. Lower body weight also leads to reduced uric acid levels in your bloodstream. High levels of uric acid contribute to gout, an inflammatory form of arthritis. Rheumatoid and psoriatic arthritis can sometimes fall into remission after weight loss.
Why Weight Loss Occurs in Rheumatoid Arthritis
A person with RA may lose weight for many reasons. Weight loss can be a side effect of RA medication or a symptom of the condition itself. Sometimes, a person with RA loses their appetite due to their symptoms, which can cause unintentional weight loss.
RA Symptoms and Appetite Loss
Rheumatoid arthritis symptoms may cause a person to lose their appetite. Pain and stiffness can make it hard to engage in exercise that maintains healthy muscle mass. They may also experience diarrhea, nausea, and vomiting.
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Medication Side Effects
According to a 2016 study, people with RA who take the medication leflunomide (Arava) are more likely to experience weight loss. This medication is a disease-modifying antirheumatic drug. It can cause diarrhea, nausea, and an upset stomach, any of which may lead to weight loss. The study examined weight gain and weight loss in more than 30,000 people who were taking RA medication, such as methotrexate, prednisone, or leflunomide.
Rheumatoid Cachexia
Being underweight can certainly be a problem for people with RA. The same pro-inflammatory cytokines, such as TNF, that damage the joint tissue in people with RA can also lead to weight loss, muscle wasting, and weakness. This condition, referred to as rheumatoid cachexia, is typically seen in those with severe disease, frequently smokers, and is linked to increased infections, osteoporosis, and poorer functional abilities. If your doctor has prescribed a TNF inhibitor to control your RA, that may also help you rebuild muscle and gain weight.
The Risks of Unintended Weight Loss in RA
Some people with this form of arthritis try to lose weight to improve their health and alleviate their symptoms. This can be a positive step for RA management if a person is overweight or obese. It may also help to improve overall health or other existing conditions. However, unwanted and unintended weight loss may harm a person who had a healthy weight or was underweight.
Research from 2017 followed 1,600 United States veterans with RA. The researchers weighed participants on a regular basis and studied the rates of weight loss and mortality. At the conclusion of the study, the authors determined that weight loss was a predictor of death from cardiovascular disease or cancer. They also found that underweight people with RA were more likely to die from respiratory causes. The researchers concluded that complications of underlying illness may cause the increased risk associated with sudden weight loss or being underweight.
According to the Arthritis Foundation, leaner people with RA may experience more joint damage than people with obesity. This may result from the presence of adiponectin, an inflammatory protein. However, fully understanding the link requires further research. However, people with obesity are more likely to experience progressive joint damage in their weight-bearing joints, which are under added strain.
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A study published in Arthritis Rheumatol in 2017, which followed women in the Nurses’ Health Study (NHS) found that severe weight loss during the early RA period was associated with increased subsequent mortality risk for women with and without RA. The study identified incident RA during the Nurses’ Health Study (1976-2016) and created a comparison cohort, matching each RA case with up to 10 non-RA comparators by age and year of RA diagnosis (index date). Among 121,701 women, 902 developed incident RA, matched to 7,884 non-RA comparators. Peri-RA weight loss >30 lb had HR of 2.78 (95%CI1.58-4.89) for mortality compared to stable weight; the comparison cohort had similar results (HR 2.16, 95%CI1.61-2.88). Weight gain >30 lb had no association with mortality among RA (HR 1.45, 95%CI0.69-3.07) or comparators (HR 1.19, 95%CI0.89-1.59).
Maintaining a Healthy Weight with RA
If a person with RA experiences unwanted weight loss, they should talk with their doctor. Inform the doctor about any other symptoms, such as appetite loss, nausea, vomiting, and weakness. The doctor can evaluate the medications a person is taking and help identify the cause of weight loss. Ideally, a doctor can make dietary recommendations and any necessary adjustments to medication to help a person maintain a healthy weight.
Dietary Recommendations
There is a huge amount of dietary advice aimed at people with RA. The following is a summary of dietary recommendations. Altering your diet to help your RA/JIA symptoms is very individual. Auto-immune conditions are complex. Keep a food and symptom diary, monitoring what you eat the symptoms you have. Boost omega 3 levels by eating oily fish or taking supplements.
Carrying too much weight is not good for joint health and mobility. Excess fat can increase inflammation by further activating your already over-active immune system. In particular, ‘visceral fat’ (fat around the abdominal area) can cause inflammation. Being underweight can also cause problems, as you may be low in muscle mass needed to support the joints. If you are overweight, follow the concepts in the Mediterranean Diet. Focus on whole foods and limit processed and refined carbohydrate foods.
The Mediterranean diet (MD) is rich in fruits, vegetables, whole grains, olive oil, and fish. Research suggests that a MD can improve RA/JIA. A MD diet can reduce disease activity and improve physical function. This may be due to high levels of antioxidants and polyphenols (plant chemicals). Research has shown that following a Mediterranean diet can improve symptoms of RA. This included reduced swollen and tender joints and duration of morning stiffness. A MD diet can increase weight loss and lower the risk of diabetes and cardiovascular disease. It can also lower the risk of certain cancers.
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Increase colorful fruit and vegetables in each meal. Aim for one half to two thirds of the plate to be non-starch vegetables. This includes greens, mushrooms, squashes, beets, cauliflower or broccoli. Eat fish, especially oily fish (important enough to have its own section). Don’t eat on-the-go. Life can be busy sometimes, but food is better digested when eaten at a slower pace. Avoid sugary drinks and limit Omega 6 fats such as vegetable and seed oils. Limit red meat especially processed meats. Focus on whole grains like quinoa, brown rice and bulgur wheat rather than refined grains. Limit alcohol. Build your plate around lean protein, healthy fats and non-starchy vegetables.
Increase fibre-rich foods, prebiotic foods and fermented foods to keep a healthy microbiome. Fermented foods are probiotic foods which can feed the bugs we wish to increase and crowd out those we don’t want. Take out refined carbohydrates, sugars and processed foods.
Omega 3 fatty acids play an important role in the inflammatory response in the body. Evidence suggests that omega 3 (from oily fish or supplements) can improve RA/JIA symptoms. The amount of omega 3 fats necessary to improve your RA/JIA symptoms is around 3g per day. Eating oily fish 2 or 3 times a week provides a reasonable intake of omega 3.
Antioxidants are substances that can prevent or delay some types of cell damage. Fruits and vegetables contain antioxidants. Eating foods which are rich in antioxidants on a regular basis can benefit your health. Brightly colored varieties of fruit and vegetables are particularly good sources of antioxidants.
Choose organic whole milk or calcium-enriched products. Vitamin D deficiency is more common in people with RA. Evidence suggests this can lead to more rapid disease progression. It is important for anyone with an auto-immune condition to check their vitamin D levels.
A gluten free diet can also be of particular benefit to those with Coeliac Disease. They can also help those with a less severe sensitivity to gluten.
Making changes to diet and adding supplements is very individual. A food and symptom diary can help you to identify food types that may worsen your RA/JIA symptoms.
Exercise Recommendations
Increasing low-impact exercise - like walking or swimming - to 150 minutes per week is an excellent strategy to jump-start weight loss. Though it may seem counterintuitive to work joints affected with arthritis, gentle motion reduces inflammation and improves blood flow, two factors that help to ease arthritis symptoms.
Exercise plays an important role in managing RA and JIA. A good exercise routine can improve joint function and reduce stiffness and inflammation. Exercise can increase the function of synovial fluid, which sits inside the joint. Synovial fluid helps protect joints and reduces friction between bones. Exercise can also lower pro-inflammatory proteins called cytokines, which play an important role in your immune system. The best exercise is the one that you do. It could be walking, swimming, dancing, tai-chi or yoga for example. Find something you enjoy that is within your limits and be consistent. It may be worth speaking to a fitness professional with some understanding of RA and JIA.
The Impact of Weight Loss on RA Disease Activity
A study published in Int J Clin Rheumtol in 2018 found that clinically relevant weight loss (≥5 kg) was associated with improved RA disease activity in the routine clinical setting. The study included RA patients seen at routine clinic visits at an academic medical center, 2012-2015. They included patients who had ≥2 clinical disease activity index (CDAI) measures. They identified visits during follow-up where the maximum and minimum weights occurred and defined weight change and CDAI change as the differences of these measures at these visits. They defined disease activity improvement as CDAI decrease of ≥5 and clinically relevant weight loss as ≥5 kg. They performed logistic regression analyses to establish the association between improved disease activity and weight loss and baseline BMI category (≥25 kg/m2 or <25 kg/m2).
The results showed that patients who were overweight/obese and lost ≥5 kg had three-fold increased odds of disease activity improvement compared to those who did not (OR 3.03, 95%CI 1.18-7.83). Among those who were overweight/obese at baseline, each kilogram weight loss was associated with CDAI improvement of 1.15 (95%CI 0.42-1.88).
The Rheumatologist's Perspective
Rheumatologists have observed how patients with obesity often experience more severe rheumatoid arthritis symptoms, including higher levels of joint pain, stiffness, and fatigue. They may also respond less effectively to treatment, especially biologic medications designed to target specific immune pathways.
Obesity and Inflammation: A Toxic Partnership
Obesity doesn’t just affect the scale - it affects your immune system. Fat tissue is not merely a passive energy reserve. It acts like an endocrine organ, releasing inflammatory proteins known as cytokines and adipokines. These substances - like leptin and resistin - promote chronic, low-level inflammation throughout the body. This systemic inflammation can contribute to the onset of rheumatoid arthritis and make existing RA more difficult to manage.
Obesity Increases the Risk of Developing Rheumatoid Arthritis
Research has shown that individuals with obesity are 37% more likely to develop RA compared to those with a healthy weight. This risk is even more pronounced in women under the age of 55. In fact, being overweight as early as age 18 is associated with an increased risk of developing RA later in life.
Gut Health, Autoimmunity, and Obesity
Emerging research has linked obesity to changes in the gut microbiome - shifts that can disrupt immune balance and contribute to autoimmune disease development, including rheumatoid arthritis. An imbalanced gut microbiome may trigger the activation of Th17 cells and the formation of anti-citrullinated protein antibodies (ACPAs), both of which are involved in RA’s autoimmune processes.
Added Joint Stress from Obesity = Added Pain
While the immune system is the main player in rheumatoid arthritis, it’s important not to overlook the impact of mechanical stress. Extra weight puts added pressure on weight-bearing joints such as the knees, hips, and ankles. Although this kind of joint stress is typically associated with osteoarthritis, it can exacerbate RA symptoms as well - particularly in patients already coping with inflammation.
The Challenge of Treating Rheumatoid Arthritis in Patients with Obesity
Studies have found that patients with obesity often experience reduced effectiveness of disease-modifying antirheumatic drugs (DMARDs), including both traditional and biologic agents. They also tend to report greater functional impairment, as measured by health assessment questionnaires.
Fortunately, there’s good news: for individuals living with rheumatoid arthritis, even modest weight loss can lead to meaningful improvements. Shedding excess weight may:
- Reduce systemic inflammation
- Improve response to medications
- Decrease joint pain and swelling
- Improve physical mobility and quality of life
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