A food intolerance is difficulty digesting certain foods and having an unpleasant physical reaction to them.It causes symptoms, such as bloating and tummy pain, which usually happen a few hours after eating the food.

In general, people who have a food intolerance tend to experience tummy pain, bloating, wind and/or diarrhoea or skin rashes and itching. These symptoms usually happen a few hours after eating the food. It can be difficult to know whether you have a food intolerance as these are general symptoms that are typical of many other conditions.

Try keeping a food diary, noting what foods you eat, any symptoms you have after eating these foods and when these symptoms happen

Once you have an idea of which foods may be causing your symptoms, you can try excluding them from your diet one at a time and observing the effect this has.

Try cutting out the suspected food from your diet for 2 to 6 weeks and see if your symptoms improve, then reintroduce the food to see if symptoms return.

You may find you can tolerate a certain level and you only get symptoms if you have more than this amount.

If you're confident you are intolerant to a particular food, the only way to manage this is to stop eating the food for a while and then reintroduce small quantities while monitoring how much you can eat without causing symptoms.Check food labels to see which sorts of foods to avoid.

If you think your child may have a food intolerance, check with a GP or dietitian before eliminating foods from their diet, as a restricted diet could affect their growth and development. Cows' milk, for example, is an important source of calcium, vitamin D and protein.

A food allergy is when the body's immune system reacts unusually to specific foods. Although allergic reactions are often mild, they can be very serious. Symptoms of a food allergy can affect different areas of the body at the same time. Some common symptoms include: an itchy sensation inside the mouth, throat or ears, a raised itchy red rash (urticaria, or "hives"), swelling of the face, around the eyes, lips, tongue and roof of the mouth (angioedema) and vomiting

Food allergies happen when the immune system - the body's defence against infection - mistakenly treats proteins found in food as a threat. As a result, a number of chemicals are released. It's these chemicals that cause the symptoms of an allergic reaction. Almost any food can cause an allergic reaction, but there are certain foods that are responsible for most food allergies.

Foods that most commonly cause an allergic reaction are:

• milk
• eggs
• peanuts
• tree nuts
• fish
• shellfish
• some fruit and vegetables

A food intolerance is not the same as a food allergy. Here's how to tell the difference.

A food allergy:

• is a reaction by your immune system (your body's defence against infection). Your immune system mistakenly treats proteins found in food as a threat
• can trigger allergy symptoms, such as a rash, wheezing and itching, after eating just a small amount of the food (these symptoms usually happen quickly)
• is often to particular foods. Common food allergies in adults include fish and shellfish and nut allergies. Common food allergies in children include milk, eggs, fish, peanuts and other nuts
• can be life-threatening

A food intolerance:

• does not involve your immune system - there is no allergic reaction, and it is never life-threatening
• causes symptoms that happen gradually, often a few hours after eating the problem food
• only results in symptoms if you eat a substantial amount of the food (unlike an allergy, where just traces can trigger a reaction)
• can be caused by many different foods

Be prepared - if you know you have an allergy to something, do your best to avoid it. For example, if you have hay fever try and avoid being outside on high pollen count days; try and keep doors and windows closed to reduce the amount of pollen coming in; don't dry your clothes or bedding outside; and change your clothes when you come inside.

Communicate - let others around you know about your allergy - and what treatment you use (i.e. where do you keep your epipen, just in case the worst happens.)

Speak to your GP and take any medications they recommend, and remember to carry them with you.

Get to know the symptoms (especially of anaphylaxis) so you can help yourself and others. Each person may react slightly differently so it is good to know the standard symptoms.

Some people no matter how hard they try to lose weight they cannot achieve their goal due to their food intolerances. Here's how food intolerance test can help you lose weight .When you eat something you're intolerant to, it can cause your digestive tract to become inflamed, often resulting in symptoms similar to those of IBS (irritable bowel syndrome).

Because our digestive system is closely linked to our hormones, this causes the adrenal glands - which are situated above our kidneys - to secrete hormones which can make our insulin levels and blood sugar fluctuate. These changes encourage the body to store fat rather than processing calories efficiently.

Over time, this means that undiagnosed intolerances will cause you to put on weight. Because your weight gain could be hormonal, lifestyle changes such as dieting and exercise are unlikely to make much difference if you don't also cut out the food that's causing the reaction.