Tips for Healthy Weight Gain With IBS

Gaining weight with irritable bowel syndrome (IBS) can be difficult, especially if you are controlling your symptoms with a restrictive diet. If you have IBS and have been dealing with unintentional weight loss, try eating smaller, more frequent meals full of IBS-friendly foods like grilled chicken, eggs, and healthy oils.

This article will help you learn how to gain weight healthily with IBS.

Gaining Weight With IBS

Weight loss or weight gain are not symptoms of IBS. Rather, weight changes occur due to the food choices you make in trying to control symptoms or because symptoms keep you from being as active as you would like.

Avoiding certain trigger foods may improve your symptoms but also cause unintentional weight loss. Fortunately, you can correct this by adding certain IBS-friendly foods to your diet.

It's important to seek medical advice if you are experiencing unexplained weight loss, as this can be a sign of underlying medical conditions, like celiac disease and inflammatory bowel disease.

Trigger Foods

It's common that those with IBS find that certain foods trigger IBS symptoms, especially foods that contain high amounts of fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs).

FODMAPs are short-chain carbohydrates that are poorly absorbed by the small intestine and attract water as it passes through it. Furthermore, FODMAPs are fermented by bacteria that exist in the colon, which produces gas.

Foods that are known to be high in FODMAPs include:

  • Wheat
  • Cow, goat, and sheep milk
  • Legumes (chicken peas, lentils, baked beans)
  • Garlic
  • Onions
  • Okra
  • Apples
  • Pears
  • Watermelon
  • Cauliflower
  • Mushrooms

Cutting back on insoluble fiber, alcohol, and caffeine if they're a regular part of your diet may be a good idea to see if your IBS symptoms improve, as some people experience IBS symptoms with these foods. Spicy foods are also associated with IBS, so you may want to steer clear of those as well.

Foods that cause IBS symptoms for one person may not cause it for another. Be sure to monitor which foods cause your IBS symptoms so that you can adjust your nutrition habits accordingly.

The Low FODMAP Diet

A well-known diet designed for IBS is known as the FODMAP diet. It's a diet focused on decreasing the intake of foods containing high amounts of FODMAPs and replacing them with foods low in FODMAPs.

Eating a low FODMAP diet can help you control your IBS symptoms. Many of these foods are also low in fat and calories, however, so if you're having trouble maintaining your weight on this diet, make sure to include foods like nuts and seeds, fruits, and healthy fats.

Some common foods that are low in FODMAPs include:


  • Banana
  • Blueberry
  • Grapes
  • Kiwi
  • Lemon
  • Lime
  • Mandarin oranges
  • Olives
  • Orange
  • Passion fruit
  • Pineapple
  • Raspberry
  • Strawberry


  • Bell pepper
  • Carrot
  • Cucumber
  • Green beans
  • Lettuce
  • Potato
  • Spinach
  • Tomato


  • Artificial sweeteners not ending in “-ol” (e.g., sucralose, aspartame)
  • Glucose
  • Maple syrup
  • Sugar

Hard cheeses:

  • Parmesan
  • Cheddar
  • Swiss

In addition, substituting wheat products with wheat-free options and dairy products with lactose-free foods can allow you to enjoy different types of foods without the increased risk of getting IBS symptoms.

Meal Ideas

Empty plate and place setting
Jorg Greuel/The Image Bank/Getty Images

The traditional "three squares" may not be a good fit for you. Large meals, in particular, may cause IBS symptoms. Instead, it might be better to plan your day around four small- to medium-sized meals, especially on a consistent schedule. This will allow you to take in some extra calories without putting you at risk for an IBS attack.

Adding IBS-friendly, high-protein foods like grilled or baked chicken and fish, tofu, eggs, almonds, and chickpeas to your meals can be good for building muscle and increasing weight.

Healthy oils like coconut oil and extra virgin olive oil are nutrient-rich, high-calorie foods that are low in FODMAPs and are known to have various health benefits. These oils can supplement various foods and can be added to smoothies and coffee.

In an effort to cope with or to try to prevent IBS symptoms, you may find yourself skipping meals. Sometimes this is because of the misguided thought, "If there is nothing in there, nothing can come out." However, the large intestine constantly produces stool. Thus, this strategy is no guarantee that symptoms won't occur.

The other problem with the "skipping meals" strategy is that it can contribute to unhealthy weight loss and possibly other health problems, as you may not be putting enough nourishment and nutrients into your body.

The ultimate goal in IBS management is to have a digestive tract that works smoothly and regularly. You can help this process along by eating your meals regularly and consistently.

Snack Ideas

close-up of peanut butter
Glow Cuisine/Glow/Getty Images

Snacking one to three times a day is a great way to add calories to your diet. Foods like nuts and seeds are convenient and portable snack options. They generally contain healthy fats and are a good source of protein, fiber, and a whole host of vitamins and minerals. Nut butters can even be spread on fruit, added to smoothies, or simply enjoyed licked off of a spoon.​

Here are some IBS-friendly nut and seed options:


  • Almonds (limit 10)
  • Brazil nuts
  • Hazelnuts (limit 10)
  • Macadamia nuts
  • Peanuts
  • Pecan
  • Pine nuts
  • Walnuts


  • Chia
  • Pumpkin
  • Sesame
  • Sunflower

Some of the low FODMAP fruits and vegetables mentioned earlier are great snack options as well. Fruits like grapes and bananas and vegetables like carrots and cucumbers are especially easy to take on the go.


Sometimes, unintentional weight loss may occur from not eating as much so that IBS symptoms don't develop. However, certain foods are known not to trigger IBS symptoms, and adding them to your diet can help ensure healthy weight gain.

A Word from Verywell

Your IBS symptoms may have led you to alter your eating habits, resulting in you losing more weight than you would've liked. But don't worry. You can gain back weight by adding foods to your diet that are less likely to cause IBS symptoms. If you feel that you need additional guidance with your diet, try consulting an IBS dietitian.

Frequently Asked Questions

  • Can IBS cause weight loss?

    IBS itself does not cause weight loss. Weight loss may occur due to eating less as a way to avoid IBS symptoms.

  • Does IBS affect your appetite?

    Loss or gain of appetite is not a direct symptom of IBS. However, IBS symptoms like stomach pain and factors associated with IBS, such as stress, may affect your desire to eat.

  • Does IBS make you absorb less calories?

    Not necessarily. IBS is not the same as malabsorption syndrome, though there can be similar symptoms between the two. Foods high in FODMAPs are generally absorbed poorly.

    However, for those with IBS, symptoms may develop from eating such foods, which may lead to eating less as a way to avoid symptoms. This can result in less caloric intake.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Gaddey HL, Holder K. Unintentional weight loss in older adults. Am Fam Physician. 2014;89(9):718-22.

  2. Dugum M, Barco K, Garg S. Managing irritable bowel syndrome: The low-FODMAP dietCleve Clin J Med. 2016;83(9):655-662. doi:10.3949/ccjm.83a.14159

  3. Cozma-Petrut A, Loghin F, Miere D, et al. Diet in irritable bowel syndrome: What to recommend, not what to forbid patients! World J Gastroenterol. 2017;23(21):3771–3783. doi:10.3748/wjg.v23.i21.3771

By Barbara Bolen, PhD
Barbara Bolen, PhD, is a licensed clinical psychologist and health coach. She has written multiple books focused on living with irritable bowel syndrome.