But what about shifting the times at which you eat? Can you reduce inflammation, lose weight, and improve other aspects of your health by eating at certain times of day and not others? This type of eating plan, known as intermittent fasting (IF), has become popular in recent years. Some people with RA use IF for weight loss, and others say it helps them feel better overall. But most of the talk about the benefits of IF are based on small studies and people’s anecdotal experiences. There isn’t a lot of research confirming whether it is more valuable than other dietary approaches. Although there are many versions of IF, each one involves some periods of normal eating and other periods of severe calorie restriction or abstaining from food. Because of the potential benefits for reducing inflammation, some people believe that those with rheumatoid arthritis could  benefit from an intermittent fasting approach. But several recent studies have not found IF to be superior to other weight-reduction methods. Still, there is likely little danger in trying it. “For most people, it can be safely done, but always check with your doctor and consult a registered dietitian nutritionist to discuss the eating pattern that is best suited to your health profile and desired outcomes,” says Ellen Liskov, RDN, of Yale New Haven Hospital Center for Nutrition and Wellness in Connecticut. Here are six things people with RA should know.

1. There Are Many Types of Intermittent Fasting, and Not All of Them Work for Everyone

Intermittent fasting is an umbrella term that spans a variety of eating plans. With all of them, you are encouraged to drink water, teas (especially herbal teas), and black coffee during the fasting periods. Some of the most common types of IF include:

Selected Fasting Days Some people pick one or more days of the week to barely eat at all. During the other days, they eat normally or perhaps even more than they would otherwise.5:2 Fasting This common IF approach allows for normal eating without calorie counting on five days each week. On two days (eater’s choice, but most people don’t do them consecutively), calories are severely restricted to about 500 calories a day for women and 600 per day for men. The idea behind both this approach and selected fasting days is that if, say, chocolate cake or creamy pasta beckons, it’s easier psychologically to take a pass if you know you can have it the following day — even if you ultimately don’t do it.Time-Restricted Eating (TRE) This is another popular IF method. People select a window of time during the day to stop eating. Variations on this method are generally described by the number of hours that you are eating and the number of hours that you are not (see below).12:12 This is a TRE approach in which you eat regularly during a 12-hour span, typically during daytime. After you finish dinner, say at 8 p.m., you don’t eat again until breakfast at 8 a.m. This is the type of IF plan preferred by the Yale dietitian nutritionist Liskov.16:8 Another widely used TRE approach, this version has a longer fasting time and a smaller eating window. Instead of eating breakfast at 8 a.m., you keep fasting until around noon, meaning all your calories for the day are consumed within just eight hours.

2. Research Hasn’t Confirmed IF’s Potential for Rheumatoid Arthritis

In the most targeted study involving RA, German researchers randomized 53 people with rheumatoid arthritis to either a seven-day fast followed by a few months on a plant-based diet or three months of a conventional anti-inflammatory diet recommended for people with RA. The researchers wanted to see whether fasters’ disease symptoms (measured by the Health Assessment Questionnaire Disability Index, or HAQ-DI) and quality of life might be more improved with one versus the other. The results of the research, known as the NutriFast-Study, were published in Frontiers in Nutrition in November 2022. It turned out that the fasting group did improve their HAQ-DI scores rapidly after the fasting week, while the other group exhibited a more slow and steady improvement. By the end of the three-month study, however, there was no difference between the two groups in terms of RA function and disability. Perhaps most important, the authors stated that “both dietary approaches had a positive effect on RA disease activity and cardiovascular risk factors in patients with RA.” So, it isn’t that the IF diet wasn’t helpful, just that it was not more helpful than the anti-inflammatory diet generally recommended for people with RA. Similar findings came from a review of 42 studies that tested IF in overweight people (but not those with RA). The research, published in Biological Research for Nursing in May 2022, found that the method did not lead to long-term differences in anti-inflammatory effects between IF eaters and those with other dietary approaches. Another study of people with RA involving fasting did find some benefits though. The research took place during Ramadan, a holiday during which observant Muslims fast for 30 days, from dawn to dusk (meaning a 12:12 or longer intermittent fast). In this study, published in 2021 in Clinical Rheumatology, 35 people with RA were assessed for disease activity before, during, and three months afterward. Disease activity was found to be significantly decreased during the fasting month and in the months following it. The benefits began to fade at around the three-month mark, however, leading researchers to recommend that people with RA consider routinely doing this type of fast every three months. Some early trials have shown improvement in RA symptoms with fasting, but “symptoms seemed to recur” when the fasting stopped, says Betty Hsiao, MD, a rheumatologist at Yale Medicine and an assistant professor at the Yale School of Medicine. Largely because of the lack of solid research on fasting diets, when France’s Society for Rheumatology released recommendations about the best weight loss eating plans in 2022, they recommended that people with rheumatic diseases stick with a Mediterranean diet and avoid plans involving fasting. Aside from reducing inflammation, many people with RA may find IF helpful as a way of managing their weight, as a number of small studies on IF in the general population have shown that it may be effective as a weight loss tool. According to a review published in JAMA Network Open in 2021, some types of intermittent fasting, notably 5:2 or a similar modified alternate-day fast, have resulted in a moderate amount of weight loss, according to moderate- to high-quality evidence. And the Biological Research for Nursing review found that when it came to losing weight, the majority of studies reviewed found the method does result in dropped pounds that were sustained over time, although not more often than with other calorie-restricting plans.

3. IF Might Help Other Conditions That Affect People With RA

In addition to potential weight loss and a reduction of RA disease activity, limited research hints at the possibility that IF may help with heart and blood-sugar markers, which are both especially important to people with RA who are at increased risk of developing heart disease. The JAMA Network Open review found that adults on IF diets had some improvements in low-density lipoprotein (LDL) cholesterol, total cholesterol, triglycerides, and blood pressure, as well as blood sugar and fasting insulin.

4. There Are Modified IF Plans to Consider

Some experts propose a modified type of fast known as a fasting mimicking diet. This diet allows for a normal amount of calories on most days but restricts them severely for five days every month. Proponents say that this approach is easier to follow than diets requiring more frequent calorie restrictions. Scientists have found that in mice, this type of diet promotes anti-inflammatory effects, and some researchers propose that it may also do the same in people. A company called ProLon sells nutritionally balanced, low-calorie, plant-based energy bars, soups, snacks, beverages, and supplements that can be eaten during the five-day fast.

5. Be Especially Careful if You Take Morning Medicines

Some rheumatoid arthritis medicines are prescribed to be taken with meals. Hydroxychloroquine, for example, is generally prescribed once or twice a day with a glass of milk or a meal, which decreases the chance of nausea. If a person generally takes this drug with breakfast, a 16:8 plan or 5:2 plan may not work. Oral steroids are similarly recommended to be taken with food or milk to keep stomach upset at bay. Still, if you are on oral medications, it is possible to find an IF plan that can work for you.

6. Check With Your Doctor Before Starting a New Diet

It’s important to clear any new eating plan with your physician, especially if the plan severely restricts calories on some days or a portion of every day. Remember that what you eat is always going to be more important than when you eat it. A junk food diet crammed into eight hours of the day is not going to be as beneficial for your RA as a low-inflammatory, healthy eating plan stretched over more time. If future research bears out the benefits of IF for people with RA, doctors could one day prescribe it to their patients, Dr. Hsiao says. But for now, “more evidence is needed prior to being able to recommend a specific fasting diet to patients with RA,” she says.