Feeling sick after eating is certainly unpleasant, especially if it happens often. Luckily, it’s not usually a major cause for concern.
Sometimes, however, nausea after a meal can point to an underlying health condition.
In this article, we explore 14 reasons why you might feel sick after eating. You’ll learn tips for easing this feeling, other symptoms to watch for and when to speak with a doctor.
Possible reasons why you feel sick after eating
Let’s run through some reasons why you might feel nauseous after a meal or a snack.
1. Gastroparesis
Gastroparesis is when food stays in your stomach longer than it should before it travels down to your intestines. This issue is also called delayed gastric emptying.
How common is it? In the United Kingdom, around 14 in 100,000 people have gastroparesis. So, fewer than 10,000 people in the country experience it.
If you develop gastroparesis, you might also:
- start feeling full more quickly than usual
- have a poor appetite
- experience bloating
- have a sore tummy
- have excess wind
- experience heartburn
If you’ve had these symptoms for a while, you might also be losing weight.
Doctors don’t always know why gastroparesis develops, but it’s usually linked to type 2 diabetes.
If you think you have gastroparesis, make an appointment with your doctor.
2. Overeating or eating too fast
You might feel sick after eating if you’ve eaten too much or too quickly. These issues can be linked: people who eat quickly tend to eat more.
The nausea should pass as your stomach empties its contents into your intestines.
Here are some strategies for the future:
- Reduce your portion size – using smaller plates and bowls can help.
- Eat more often but have smaller meals.
- Don’t let yourself get too hungry.
- Chew your food thoroughly.
- Put down your cutlery or take a sip of water between mouthfuls.
Also, try to avoid screens during meals. If we’re distracted by a laptop or TV, we tend not to notice how much we’re eating.
3. Stomach bug
When we feel sick after eating, a common culprit is an infection called gastroenteritis.
It can have a bacterial or viral cause, and kids are especially likely to develop it.
How common is it? The UK sees an estimated 17 million cases of gastroenteritis each year. So, about 1 in 4 of us get it in a given year.
If you have gastroenteritis, or a 'stomach bug', you might also be experiencing:
- vomiting (sometimes projectile)
- a fever
- muscle aches
- joint pain
- a headache
Unfortunately, there aren’t specific treatments for gastroenteritis. It’s a good idea to stay home until it passes.
Here are some other strategies:
- Do your best to stay hydrated.
- If your wee is dark, try a rehydration drink from the pharmacy.
- Get rest and good sleep.
- If you feel like having food, keep it plain: bread, rice, or simple soups or pasta dishes.
4. Food poisoning
When food is left out for too long, the bacteria in it can multiply, and eating this can make you sick. It’s especially likely when animal products are involved.
You might also get food poisoning from food that’s been contaminated during manufacturing or processing.
Bacteria called Campylobacter, Listeria and Salmonella are often responsible.
How common is it? Food poisoning is less common than it used to be, thanks to food laws and improved hygiene standards.
However, there are still around 2.4 million cases in the UK each year.
Symptoms vary, but they often include:
- feeling sick
- stomach cramps
- diarrhoea
- vomiting
- fever and chills
- aches and pains
Thankfully, food poisoning tends to improve on its own.
Staying hydrated is key, as you’re likely to lose a lot of fluids when you’re vomiting or experiencing diarrhoea.
5. Hormonal changes
Hormones have wide-ranging effects throughout your body, including your gut.
During pregnancy, hormone levels can change dramatically, and these changes often cause nausea.
Morning sickness is well-known, but you may feel sick before or after you eat at any time of day.
These strategies can help:
- eating smaller meals
- not letting yourself get too hungry
- resting – but try not to nap right after a meal
- avoiding strong tastes and smells
- avoiding spicy and fatty foods
- staying hydrated
- trying ginger or peppermint tea to ease the nausea
Feeling sick is most common between the second and fourth months of pregnancy.
It’s not usually a sign of complications, and it should go away with time. However, if the nausea is concerning, speak with your doctor.
6. Food allergies
Food allergies can also make you feel sick after eating. They develop when your immune system mistakes a certain food or component as a threat.
Some of the most common food allergies involve:
- peanuts
- tree nuts, such as Brazil nuts, pistachios and walnuts
- shellfish
- milk
- eggs
- fish
- soybeans
- wheat
- sesame
Most of the time, the symptoms pass on their own. But more severe cases can trigger anaphylaxis, a life-threatening reaction.
If you think this might be happening, seek medical attention immediately.
Alongside nausea, symptoms of a food allergy can include:
- a rash
- feeling cold and clammy
- reduced blood pressure
- increased heart rate
- a runny nose and streaming eyes
- vomiting and diarrhoea
- swelling of the face and throat
- trouble breathing
There’s no cure for food allergies. But antihistamine medications can help reduce the symptoms of less severe reactions.
Overall, the best approach is to identify and avoid your triggers.
How common are they? Food allergies seem to be on the rise in Western countries.
Around 2.4 million people in the UK have a food allergy diagnosis. That’s roughly 1 in 27 people.
7. Food intolerances
Though they’re sometimes lumped together, food intolerances are different from food allergies.
Allergies are driven by the immune system, but an intolerance means that your gut has trouble processing or digesting a certain food or component.
The symptoms of intolerances and allergies can overlap. But if you have an intolerance, your symptoms tend to be less severe and mainly gut-based.
Symptoms of a food intolerance can include:
- feeling sick after eating
- belly pain
- bloating
- diarrhoea
- excess wind
- heartburn
- headaches
Some of the most common culprits are:
- FODMAPs, a type of carbohydrate in many fruits and vegetables
- lactose, the sugar in cow’s milk.
- fructose, the sugar in fruit
- histamine, a chemical in cheeses, alcoholic drinks, processed meats, and some fruits, fish and fermented foods
How common are they? Diagnosing food intolerances is tricky – we don’t always know why they occur, and it’s hard to know how many of us are affected.
But experts estimate that up to 1 in 5 people have a food intolerance. In the UK, that’s around 13 million people.
The best way to prevent the symptoms is to identify and avoid the trigger. Keeping a food and symptom diary can help you spot the cause.
8. Gallbladder disease
When you consume fat, your gallbladder releases bile into your gut to help break it down.
If there’s an issue affecting your gallbladder, you might feel sick a short while after eating high-fat foods.
Other symptoms of gallbladder diseases include:
- pain in the upper-right section of your abdomen
- vomiting
- fever and chills
- yellowing of the skin
How common is it? In the UK, gallbladder diseases affect around 2% of females and 1% of males.
If you think you might have a gallbladder disease, speak with your doctor.
9. Heartburn or GORD
Many of us are familiar with heartburn, a burning sensation in the chest. It happens when food travels from your stomach back up into your oesophagus – the food pipe.
Because your stomach contents are acidic, this reflux can burn the sensitive lining of the oesophagus. This, in turn, can cause nausea, pain and general discomfort after a meal.
Many of us have heartburn every once in a while, but some people experience it regularly for weeks, months or years. Doctors refer to this as gastroesophageal reflux disease (GORD).
How common is it? GORD affects around 14% of people in the UK, which is around 9.4 million people.
Alongside feeling sick after eating, you might experience:
- vomiting
- an unpleasant taste in your mouth
- a cough
- inflammation of the voice box
- eroded teeth
- bloating
- burping
Your doctor may prescribe medication for GORD. The following strategies can also help minimise the symptoms:
- eating smaller portions
- sleeping with more pillows to keep your head elevated (if you have symptoms at night)
- maintaining a healthy weight
- avoiding foods and drinks that trigger your symptoms, such as caffeine, high-fat foods, citrus fruits, carbonated drinks and minty teas
If you have heartburn multiple times a week and trouble swallowing or any severe symptoms, make sure to visit your GP.
10. Stress, mood and mental health
There are complex nervous system connections between your gut and brain. Collectively, these connections are called the gut-brain axis.
Stress, mood and mental health conditions can influence your levels of stress hormones. This can cause gut symptoms, such as:
- feeling sick
- heartburn
- diarrhoea
- constipation
How common are they? Stress affects everyone to a certain degree. Mental health conditions, including depression and anxiety disorders, are common, affecting around 1 in 6 people in England and around 11 million people in the UK.
If stress or mental health conditions lead to nausea after you eat, it’s important to identify the root cause.
For stress, simple techniques like breathing exercises and yoga can help some people.
If you believe that you have a mental health condition, speak with your doctor, who may prescribe talking therapy or medication.
11. IBS
Irritable bowel syndrome (IBS) is a common gut disorder.
It causes a range of symptoms, including:
- feeling sick (though this is less common)
- stomach cramps and pain
- bloating
- diarrhoea or constipation
- excess wind
- back pain
- fatigue
- a sudden urge to poo or pee
How common is it? IBS affects about 1 in 20 people in the UK, which is more than 3 million people.
Certain lifestyle changes can help, including:
- limiting fatty, spicy and processed foods
- not having more than three portions of fruit per day
- reducing caffeine
- avoiding fizzy drinks and alcohol
- keeping active
- reducing stress
If you think you have IBS, speak with your doctor, who may prescribe medication. Also, keeping a food and symptom diary can help you identify your triggers.
12. Diabetes
Gastroparesis – when food moves through your stomach too slowly – is more common in people with type 2 diabetes. As we mentioned earlier, it can cause nausea after a meal.
Meanwhile, having low or high blood sugar can also make you feel sick. These are issues that people with diabetes contend with.
How common is it? Diabetes affects around 4.4 million people in the UK, or around 1 in 15 people.
Other symptoms of low blood sugar can include:
- feeling shaky, irritable, confused, nervous or anxious
- sweating and chills
- an increased heart rate
- lightheadedness
- hunger
- feeling sleepy, weak or low in energy
- blurred vision
- tingling or numbness in the lips, tongue or cheeks
Other symptoms of high blood sugar include:
- peeing more than usual
- thirst
- tiredness
- a headache
- blurred vision
Managing diabetes well eases these symptoms.
If you think you might have diabetes, visit your doctor to get tested. And if your diabetes needs to be managed better, let your doctor know.
13. Pancreatitis
Pancreatitis is a serious condition caused by an inflamed pancreas.
Nausea can be a symptom, but the most prominent symptom is upper-abdomen pain that can spread to your back.
How common is it? Pancreatitis affects around 0.2% of people in the UK each year, which is around 140,000 people annually.
Seek medical attention if you think you have pancreatitis.
14. Medications
Many types of medicine can cause nausea. In general, this side effect stops once you stop taking the drug.
If any side effect is distressing, speak with your doctor, who may be able to prescribe something else.
Drugs that can cause nausea include:
- antibiotics
- antidepressants
- aspirin
- chemotherapy
- opioids
- certain over-the-counter products, like iron supplements
It’s important to speak with your GP before you stop taking any prescribed medication.
Home remedies
If you feel sick after eating, the strategies below may help.
But if your symptoms are severe, please skip down to the next section. It’s about when to seek medical care.
Some approaches to easing nausea after a meal include:
- having easy-to-digest foods, like rice, crackers or dry toast, if you feel up to it
- having smaller meals but eating more often
- staying hydrated
- chewing gum or sucking on mints
- having ginger products, like ginger tea
- limiting or avoiding dairy products for a few weeks to see if it helps
When to seek medical help
Most often, feeling sick after eating is not a medical emergency.
But get help right away if the nausea occurs with any of these symptoms:
- chest pain, especially if it’s sudden or severe
- sudden or severe abdominal pain
- blood in your vomit or dark vomit
- trouble breathing
- a fever and neck stiffness
- a severe headache
- confusion or blurred vision
- bleeding from your bum
Summary
Feeling sick after eating is unpleasant, but it’s rarely a cause for concern.
The nausea can stem from a wide range of conditions, including food allergies or intolerances, infections, diabetes, IBS, GORD, or problems with your pancreas or gallbladder.
Lifestyle factors, such as eating too much or too fast, can also cause nausea after eating.
Changes in stress hormone levels can play a part, as can certain medications.
Some self-care strategies may help, but if your symptoms concern you or get worse, seek medical help.
To learn more about other gut health topics, visit Symprove’s Gut Hub.
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