words by Dr Naomi Newman-Beinart (PhD)
As a nutritional therapist, one of the most common things I hear from clients is: “I don’t understand what’s changed. I am eating really well, but just feel bloated all the time”. They’re eating what they believe is a healthy diet. They’re making an effort to exercise. They’re investing in supplements, prioritising their wellbeing and trying to look after themselves. Yet, they’re still struggling with bloating, fatigue, brain fog, headaches, skin flare-ups or stubborn weight gain that simply doesn’t seem to make sense.
Many people assume these symptoms are just part of getting older, stress, hormones or a busy lifestyle. Sometimes that’s true. However, one often-overlooked factor is food intolerance. In the clinic, I often see women who have spent years trying different diets, supplements and wellness trends before considering whether a food they eat every day could be contributing to how they feel. While food intolerance isn’t always the answer, when symptoms persist despite making positive lifestyle changes, it’s certainly something worth exploring.
What is a food intolerance?
Unlike food allergies, which usually trigger an immediate and sometimes severe reaction, food intolerances can be much more difficult to identify. A food allergy typically causes symptoms within minutes of eating a food and may include swelling, breathing difficulties or hives. Food intolerances are different. Symptoms can appear hours or even days after consuming a trigger food. This delayed response makes it incredibly difficult to connect the food with the symptoms. For example, you might have eggs for breakfast and develop a headache later that evening. Or perhaps you eat a sandwich at lunch and notice bloating, constipation or heartburn the following day. Because the reaction isn’t immediate, many people never realise there may be a connection. What’s particularly interesting is that many of the foods involved are foods we often consider healthy. Foods such as eggs, dairy products, oats and wheat can be enjoyed without issue by many people, but for others, they may contribute to symptoms that gradually chip away at energy levels, digestive comfort and overall wellbeing. The UK Food Intolerance Testing Laboratory, YorkTest, estimates that up to 45% of people in the UK may be living with a food intolerance, yet many continue to blame symptoms such as bloating, fatigue, headaches and brain fog on stress, hormones, or simply getting older.
Signs and Symptoms of Food Intolerance
When people think about food intolerance, they often think about digestive symptoms. While bloating, wind, abdominal discomfort and altered bowel habits are certainly common, food intolerances can affect many different areas of the body.
Potential symptoms may include:
- Bloating
- Excessive wind
- Constipation
- Diarrhoea
- Heartburn
- Fatigue
- Brain fog
- Headaches and migraines
- Joint aches and pains
- Spots and blemishes
- Eczema flare-ups
- Low mood
- Difficulty concentrating
- Unexplained weight gain
Many of these symptoms can be caused by a variety of factors, which is one reason food intolerances can be difficult to spot. However, when people start to identify patterns between certain foods and how they feel, it can often provide valuable insight into symptoms they may have been struggling with for years.
Why are food intolerances so difficult to spot?
One reason is that many of us eat the same foods repeatedly. A client may have porridge every morning, the same sandwich at lunch and similar meals throughout the week. If a particular ingredient is contributing to symptoms, the body is being exposed to it regularly, making it difficult to recognise a pattern. Interestingly, foods that people eat most often are sometimes the foods that appear to be causing the biggest issues. It’s not unusual for someone to discover that a food they’ve considered healthy and consumed daily is actually one of the foods worth investigating further.
Because symptoms can be delayed, many people simply don’t make the connection. Instead, they accept bloating after meals, afternoon energy slumps or feeling uncomfortable in their clothes as part of everyday life.
Food intolerances, inflammation and feeling your best
Food intolerances are often associated with low-grade inflammation. Inflammation is the body’s natural defence mechanism, but when it becomes ongoing, it can leave people feeling less than their best. This doesn’t mean every symptom is caused by inflammation, but many people report experiencing symptoms such as fatigue, headaches, digestive discomfort, skin issues and joint aches when regularly consuming foods that don’t agree with them. In the clinic, I often describe it as the body working harder than it needs to. Instead of feeling energised and resilient, some people feel as though they’re constantly operating with the handbrake on.
Can food intolerances affect weight and bloating?
Weight gain is rarely caused by one single factor. Hormones, stress, sleep, activity levels and overall diet all play important roles. However, many people report feeling less bloated, less puffy and more comfortable in their clothes after identifying foods that may be contributing to symptoms. Often, the biggest difference isn’t necessarily what they see on the scales, but how they feel. Improved digestion, better energy levels and reduced bloating can all help people feel more confident, motivated and comfortable in their own skin. For many women, that’s often just as important as any change in weight.
How do you identify a food intolerance?
Traditionally, people have used elimination diets to identify trigger foods. This involves removing suspected foods from the diet and then gradually reintroducing them while monitoring symptoms. While this approach can be effective, it can also be time-consuming and difficult to follow, particularly when symptoms are delayed or multiple foods may be involved. For busy people, keeping detailed food diaries and tracking symptoms over several weeks isn’t always realistic. This is one of the reasons food intolerance testing has become increasingly popular in recent years.
Thinking about testing? Here’s what to look for
One of the questions I’m often asked is whether food intolerance testing can help speed up the process of identifying trigger foods. While testing shouldn’t completely replace professional advice or be viewed as a standalone solution, it can provide a very useful starting point for people who are struggling to identify patterns on their own and want clarity on foods that they might be reacting to.
It’s also important to recognise that not all food intolerance tests are created equal. When considering testing, I would always recommend choosing a reputable provider that uses laboratory analysis, has an established track record and provides clear, evidence-based information that can be considered alongside symptoms and dietary habits. For that reason, when I am asked to provide guidance on food intolerance testing, I always advise choosing a well-established company, such as YorkTest, a UK-based, regulated laboratory. Their Premium Food Intolerance Test, £139.00, is one I recommend, as it measures IgG reactions to more than 200 food and drink ingredients, using a simple finger-prick blood sample that can be taken at home, and analysed in a laboratory.
What I particularly like is that the process is straightforward, time-efficient, and accessible to busy people, and it provides a structured starting point rather than relying on guesswork alone. Rather than removing foods unnecessarily, which can be quite stressful for people and unnecessary, testing can help focus attention on foods that may be worth exploring further. Results should always be considered alongside symptoms, dietary habits and an individual’s wider health picture. The good news is that, rather than trying to work it all out yourself, YorkTest also has a team of qualified and BANT-registered nutritionists available to support you. You can book a call, and they will help you build a diet plan and menu suggestions, and provide much more guidance on the foods you can eat.
What happens after identifying a food intolerance?
The goal is not to eliminate foods forever. Instead, many people choose to reduce or temporarily remove foods identified through testing, then gradually reintroduce them. This gives the body an opportunity to settle while helping individuals better understand how specific foods may be affecting their symptoms. There are often plenty of alternatives available. For example, someone who discovers they react to wheat may experiment with alternative grains, while someone who is sensitive to dairy may explore lactose-free products or other suitable alternatives. Importantly, identifying a food intolerance should never be viewed as a reason to unnecessarily restrict the diet. The focus should always be on maintaining a varied, balanced and enjoyable way of eating while finding practical solutions that help reduce symptoms and improve quality of life.
The benefits people often notice after elimination/restriction. Everyone’s experience is different, but many people report improvements in: - Bloating
- Digestive comfort
- Energy levels
- Mental clarity
- Skin appearance
- Joint comfort
- Sleep quality
- Overall wellbeing
Could food intolerance be affecting you?
If you’ve been struggling with persistent bloating, digestive discomfort, low energy, brain fog, headaches, skin issues or unexplained weight changes and haven’t yet found a clear explanation, it may be worth considering whether certain foods could be playing a role. Food intolerance isn’t always the answer. However, understanding how your body responds to the foods you eat regularly can be a valuable step towards creating a more personalised approach to health and wellbeing.
Whether that’s through keeping a food diary, working with a nutrition professional or exploring a reputable food intolerance test such as YorkTest, gaining more insight into your body’s unique needs can often be the first step towards feeling your best.
