When Your Favorite Foods Stop Agreeing With You
By Dr. Karen Hill
You used to enjoy a bowl of ice cream without a second thought. Now, it leaves you bloated. You’re eating more vegetables, but your stomach feels uncomfortable. And somewhere along the way, constipation became a regular concern.
It’s easy to say, “I guess I’m just getting older.”
But that explanation doesn’t tell you what to do.
Food tolerance and bowel habits can change over time. That doesn’t mean discomfort is something you simply have to accept. The goal is to understand what changed before eliminating more foods or adding another supplement.
Why foods may feel different now
One example is lactose, the natural sugar in milk. Your small intestine uses an enzyme called lactase to digest it. In many people, lactase production declines after childhood, and symptoms may become noticeable later in life. Undigested lactose can cause gas, bloating, abdominal discomfort, or diarrhea. This is different from a milk allergy.
Other foods can cause symptoms because of how their carbohydrates are digested. Intestinal bacteria ferment certain carbohydrates in foods such as beans, vegetables, and fruits, producing gas. These foods can still be nutritious. Your tolerance may depend on the amount you eat and the rest of the meal.
Medications, supplements, activity, hydration, and eating patterns can also affect bowel function. Iron supplements and some medications can contribute to constipation. Difficulty coordinating the pelvic floor muscles can make stools harder to pass, too.
Medications with GLP-1 activity, such as semaglutide and tirzepatide, slow how quickly the stomach empties and can cause gastrointestinal symptoms such as constipation, bloating, or nausea. If your symptoms started or worsened after beginning one, tell your clinician. Adjustments are often possible.
Other medical conditions can play a role. An underactive thyroid can slow the bowel. Some women notice changes in bloating and bowel habits around perimenopause and menopause, although research on the relationship remains limited. Age may be part of the context, but it should not be the whole explanation.
Before blaming the food, look at your bowel habits
Constipation and bloating often occur together. Constipation isn’t only about how many days pass between bowel movements. Hard stools, straining, and feeling that you haven’t completely emptied also matter.
Could this be irritable bowel syndrome?
Irritable bowel syndrome, or IBS, involves recurring abdominal pain associated with changes in bowel movements. Some people mainly experience constipation, others diarrhea, and some alternate between the two. Bloating is common, but bloating or constipation alone does not necessarily mean you have IBS.
IBS is a disorder of communication between the gut and brain. It can affect how the bowel moves and how strongly you feel normal digestive activity. Symptoms are real, even when routine testing shows no visible damage to the digestive tract.
New or persistent symptoms deserve an assessment before being labeled IBS, particularly when they begin later in life.
When to get checked
Arrange an evaluation for persistent symptoms or an ongoing change in bowel habits. In particular, talk with your clinician if you notice:
- Persistent or unexplained changes in bowel habits at any age, especially with a family history of colorectal cancer. Keep your routine colorectal cancer screening current as well.
- New bloating, feeling full quickly, or pelvic or abdominal pressure that is unusual for you and persists for two weeks or longer. These symptoms warrant assessment, including consideration of ovarian causes in women.
- Symptoms that wake you from sleep.
Where does the low FODMAP diet fit?
A low FODMAP diet can help some people with IBS. FODMAPs are certain carbohydrates that may be poorly absorbed and fermented by intestinal bacteria, contributing to gas and bloating. Foods containing them include onions, garlic, wheat, beans, certain fruits, and some dairy products. Portions matter, and tolerance varies.
Before starting, ask your clinician whether you should be tested for celiac disease. Cutting back on wheat first can make celiac blood tests falsely normal.
The approach has three steps:
Temporarily reduce FODMAPs
Substitute lower FODMAP foods for approximately two to six weeks and assess whether symptoms improve.
Reintroduce systematically
If the trial helps, test individual FODMAP groups in measured amounts while tracking symptoms.
Personalize your diet
Bring tolerated foods back and adjust only the foods or portions that consistently bother you.
The goal is a varied diet with fewer symptoms.
A dietitian familiar with this approach can help protect nutritional adequacy and guide reintroduction. If the trial doesn’t help, reassess the approach rather than continuing to restrict foods.
If you’ve struggled with restrictive eating in the past, talk with your clinician before starting any elimination diet, including this one.
Practical steps you can take now
Look for patterns.
For a week or two, record foods, approximate portions, symptoms, and bowel movements. Include medications and supplements. This helps distinguish an occasional reaction from a consistent trigger.
Change one thing at a time.
If milk repeatedly causes symptoms, try lactose-free milk rather than immediately removing all dairy. Some people tolerate yogurt or hard cheeses better. Preserve sources of calcium and vitamin D as you make changes.
Give fiber time to work.
Adjust how you eat.
Try smaller meals, eat slowly, and notice whether carbonated drinks worsen symptoms. Sometimes changing the amount or eating pattern helps more than removing an entire food group.
Review the whole picture.
Discuss your medications, supplements, activity, hydration, and bowel habits with your clinician. Persistent symptoms may need an evaluation for causes that food changes alone won’t address.
What about food sensitivity blood testing?
Evidence supporting MRT and ALCAT as reliable ways to identify foods responsible for digestive symptoms remains limited. They are not established diagnostic tests for food allergy or intolerance.
I offer these tests at LifeLongWeigh, and some patients have reported improvement after temporarily avoiding foods identified in their results. That improvement does not establish that the test accurately identified the cause.
My clinical perspective
I don’t want you to end up with a growing list of foods you’re afraid to eat and a cabinet full of products that haven’t helped.
Your symptoms deserve a thoughtful review. The aim is to keep your diet varied and nourishing while identifying what your body tolerates and what needs medical attention.
At LifeLongWeigh, we can review your eating patterns, medications, and supplements and develop practical nutrition changes, alongside further medical evaluation when needed.
LifeLongWeigh Clinical Pearl
The goal is a varied, nourishing diet with fewer symptoms. Food changes should come with a plan to reassess and reintroduce, while persistent symptoms deserve medical attention.
This article is for educational purposes and does not replace individualized medical evaluation, diagnosis, or treatment.