When you go out to eat with friends, you are SUPER careful with what you order and you ALWAYS make note of the nearest bathroom. You don’t know which IBS symptom it’ll be today.

It’s not just the symptoms you’re worrying about, you have this voice in your head – “Can IBS cause weight loss or will I gain weight?”

You can’t help it – you’ve been brought up thinking you had to have a certain body size.

At the same time, going on a diet right now feels impossible with all the restrictions you already have with your IBS.

Ugh! Your gut’s a mess, you’re not happy with your body and you just want to be happy and healthy like everyone else! 

Hi! I’m Melissa! As a registered dietitian and certified Intuitive Eating counselor, I hear this so often.

In this blog post, I’m going to tackle how to feel comfortable with your weight and GI (gastrointestinal) symptoms to help you understand what may be happening and how to move forward with a little more peace.  

A men's and women’s public bathroom sign attached to a brick wall.

what is IBS?

IBS is short for irritable bowel syndrome.

If you have IBS, you can experience pain with digestion, bloating, and changes in your bowel habits, including diarrhea or constipation (or – gads – both!) (1). 

IBS is tricky to diagnose. Unlike other bowel conditions, doctors can’t see any damage or evidence of IBS if they were to look at your digestive tract (1). Even more frustrating is the fact that doctors don’t know what causes IBS. This can sometimes make doctors skeptical that something is actually wrong. 

But YOU know something doesn’t feel right. And I believe you.

how do you know you have IBS?

If you are experiencing pain with digestion and frustrating GI issues (diarrhea or constipation), you may want to consider getting checked out by your doctor.

Your doctor will examine you, and ask you about your symptoms, medical history, and family history.

IBS can be diagnosed by the process of elimination. Your doctor may order other tests to rule out any other bowel diseases before they diagnose you with IBS (1).

If you have recently received a diagnosis of IBS, your doctor may have advised you to make lifestyle changes, talked about medications or supplements to improve your symptoms, and talked about stress management (2). 

If your doctor isn’t taking your concerns seriously, or attributing everything to your weight, I’d recommend seeking a new doctor. You deserve to be heard and have your concerns addressed. I have some advice on how to find a fat-friendly doctor so you can be seen for YOU, instead of your size.

If you left the office confused about how to handle your symptoms and you’re even more worried about what will happen with your weight, I can help.

First, let’s address how IBS may affect your weight.

can IBS cause weight loss or gain?

All your life you’ve been focused on your weight, which has been so up and down lately. What gives?

This new diagnosis of IBS has you spinning.

You just want to be able to eat freely and not worry about it. But this confusing pattern of symptoms and weight loss and gain is making it hard for you to feel safe eating anything at all.

IBS and weight loss

Unlike other types of GI issues (such as Crohn’s or colitis), weight loss with IBS is not as common (3).

It may be that you are following a restrictive diet to avoid your disruptive GI symptoms, in which case weight loss and anxiety around food may be more common. 

You may also experience weight loss if you are having ongoing diarrhea. Food may be traveling too quickly through your digestive system and you can’t absorb the nutrients from your food.

If you find that you are losing weight even though you’re NOT following a restrictive diet or having frequent diarrhea, you should talk to your doctor about this. 

IBS and weight gain

When you have IBS, you may experience symptoms that have the potential to impact your weight. Although IBS itself is not linked to weight gain or loss.

There are many factors that affect your body size beyond what you eat or your lifestyle – things you can’t change like your age, sex, and genetics.

Consider this – trying to lose weight for appearance or other health goals may also lead to stress that can disrupt your quality of life. 

Working on body respect and acceptance is a big part of the work I do with clients. This is hard work, especially if you’ve dieted your whole life or been criticized for your weight in the past. 

Accepting your weight means recognizing you have a unique body all your own and you can find ways to care for it! This may be hard to hear.

Let’s delve more into how your unique body is giving you feedback, how your symptoms may be impacting your weight, and what you can do about it!

A vintage blue kitchen scale weighing out 1 pound of potatoes.


Bloating is one of the most common symptoms people experience with IBS and depending on how severe your bloating is, it may be seriously impacting your quality of life (4).

Feeling really bloated can make you feel like you’ve gained weight or make your tummy bulge but it’s not actually true weight gain

“Weight” from bloating goes away when you pass gas or poop! 

Despite that, “I feel fat” is what I hear so often when my clients are experiencing bloating. 

Friendly reminder – fat is not a feeling. But I understand – you aren’t happy with how you feel, or your weight right now, or maybe you never have been content with your size.

If this is you, and “feeling fat and gross” is prevalent in your self-talk, please head over to my blog “help: I’m feeling fat and gross” and let’s work on that.

Keep in mind that even without bloating, your weight is never 100% stable. It’s normal for weight to fluctuate small amounts from day to day as a result of food and fluid balance, even if you don’t have IBS.

Try to stay focused on language that describes your symptoms. This way you hone in on what your body is telling you instead of resorting to diet extremes and restrictions without reason.

If your weight has dramatic shifts up or down, your bloating is painful or extreme, or impacts your quality of life then I would suggest you reach out to your GI doctor or dietitian. They can help make suggestions to stabilize your symptoms.

intolerance of certain foods

Sorting out your IBS symptoms can be a tricky puzzle with many pieces. Sometimes it’s just simpler to choose that kiddie puzzle with 50 pieces than getting 1000 pieces all fitting just right.

In an effort to avoid symptoms, you’ve found a small list of “safe” foods and your food choices have become less varied than when you didn’t have all these tummy troubles.

These foods may be lower fiber foods, with higher amounts of simple carbohydrates or fat, and foods that are energy dense.

You have found this small list to be the right choice for you to help improve your quality of life, right now. And choosing these foods may mean you are on the higher end of your normal weight spectrum, but you feel better.

If your list of foods that you tolerate has gotten awfully small and you think it may be contributing to your weight gain, not to worry. 

First, all of us have a weight range that is right for us biologically.

Even if you’re not at your preferred weight (or what your mom told you you oughta be to be cute), it doesn’t mean that you’re at an unhealthy weight.

In fact, body mass index (BMI) has been deemed bogus and you can learn more about how BMI is an inaccurate tool to determine health risks in one of my previous blogs. It’s a measure that healthcare professionals have looked to to help determine health risk but perhaps we need to look more holistically!

When I work with you, we think about what your specific concerns are, and your health goals, and find ways to manage them. We consider nutritional adequacy, balance, and variety – to make sure your bases are covered!

We also work on body image and gaining love and respect for your body even if it isn’t accepting foods that you may have not had a problem with before. 

I acknowledge that this is an emotional process and coping with your emotions is part of what we work on too!

A brown dog slumped on the sidewalk, looking like they have no energy.

coping with emotions

Experiencing varied symptoms such as constipation and diarrhea at the most inopportune times can be stressful. Many with GI symptoms share that they start to feel long-term stress about their symptoms. Will they ever figure it out?

On top of that, anxiety and stress can worsen your symptoms. It’s a vicious cycle.

For some, coping with these emotions is linked to emotional eating, or gaining weight. 

There’s nothing wrong with emotional eating or weight gain BUT if you have concerns about this, then I want you to consider a couple of things:

  • What are your concerns for health and how do you manage them?
  • What body image support might you need to love and respect your body when it is functioning well?

Stephanie is a past client of mine and she shared her experience in my program related to emotional eating in one of my podcasts. Have a listen if emotional eating is something that you feel you need some more support with.

I work with my clients to explore food and non-food coping skills so that emotional eating does not worsen your IBS symptoms or cause any undue guilt or body shame. 

If you are struggling with your symptoms and body weight and you’re not coping but you want to move forward, Intuitive Eating skills can be a helpful start.

Working with a registered dietitian, trained in Intuitive Eating, can help you sort through your symptoms, and what foods can work for you, so you can gain peace with food. 

should you try low FODMAPs?

If you have IBS, maybe you’ve heard of the low FODMAP diet. FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (5). Certainly a mouthful, so let’s stick with FODMAP!

This “diet” systematically removes foods containing FODMAPs to see if symptoms improve, and hopefully finds the culprit(s) (5).

Often you’ll be handed a list of high FODMAP foods to avoid and sent on your way. Leaving you to the mercy of the internet to figure out what may or may not apply to your unique situation.

The low FODMAP diet is not meant to be a permanent way of eating. It’s simply a tool to help identify foods and their link to your symptoms. It should be done temporarily and with a trained guide to help you (6).

Otherwise, it can be done incorrectly and lead you to false conclusions, and unnecessary restrictions.

This feels confusing, frustrating, and awful. Stress and confusion from experiencing symptoms and weight fluctuations have you exhausted, never mind having to figure out a whole new way of eating (without any help).

This is a difficult place to start, especially if you have a history of eating disorders or chronic dieting.

When I work with clients, I take into account your dieting history and GI symptoms so we can approach IBS holistically and sustainably.

Then we compare this with diet quality, as well as other factors like thoughts and feelings about food.

This may include keeping journals of symptoms and sharing them with me for feedback and counseling. 

You get personalized advice, but even more, you get to learn to be more intuitive with your diet overall. And that’s empowering!

key takeaways

IBS is a challenging diagnosis and can involve some trial and error with the foods you eat. This is especially true if you have a history of chronic dieting, eating disorders or body image struggles.

Weight gain can occur, but I encourage you not to rush to the latest diet.

It’s important to work on healing your gut holistically. Be patient with yourself and if you are stuck, enlist the help of someone who can help motivate you and help you progress with confidence.

When I work with my clients, I help you work on body acceptance and your Intuitive Eating skills alongside your IBS management so that you can find a sustainable way of eating.

We work together to evaluate what foods are linked to your symptoms, stress management techniques, behavioral techniques, and whether to use supplements and probiotics to help you have a more peaceful relationship with food.

Don’t give up hope! You can start feeling better with a supportive guide by your side.

Let’s work together so you can get the support you need to feel better and gain peace with your weight and eating and minimize all of those IBS symptoms that are taking over your life (and bathroom).