Expert Karen Geary’s quick guide to the most common therapeutic diets, designed to support your health, not just your waistline
We often think of diets as a way to lose a few pounds before summer, but some diets serve a far more important role – supporting chronic health conditions. From gut health to autoimmune disease, therapeutic diets aren’t about trends or quick fixes. They are targeted nutritional approaches designed to reduce symptoms, manage conditions and, in some cases, improve long-term health outcomes.
But here’s the key difference: many therapeutic diets are not meant to be followed forever. They often involve elimination phases, careful reintroductions, or a specific nutrient focus – and using them without personalised guidance can do more harm than good.
This is where professional support, such as a registered nutritional therapist or dietitian, becomes essential, especially when dealing with complex issues such as gut health, thyroid conditions, certain cancers or autoimmune disease. Here’s a quick guide to some of the most common therapeutic diets and when they might be appropriate:
Gluten-free
What it is: A diet that eliminates all gluten-containing foods (wheat, barley, rye). Essential for those with coeliac disease and often adopted by people with autoimmune conditions, such as Hashimoto’s thyroiditis, due to potential gluten sensitivity. Some people also choose to eliminate gluten “mimics” such as corn, oats and even dairy, as these can cross-react in sensitive individuals.
What it’s great for: Managing coeliac disease, non-coeliac gluten sensitivity and may help reduce inflammation in autoimmune thyroid disorders.
Watch outs: It’s not inherently healthier or designed for weight loss. Many gluten-free packaged foods are highly processed.
Focus on whole, naturally gluten-free foods and seek testing before self-diagnosing gluten intolerance or removing entire food groups unnecessarily.
Low FODMAP
What it is: A short-term elimination diet that reduces fermentable carbohydrates known as FODMAPs (Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols), which can trigger bloating, pain and IBS symptoms. It is designed to be followed in phases, with gradual reintroduction.
What it’s great for: Clinically proven to reduce symptoms of IBS (irritable bowel syndrome), SIBO (small intestinal bacterial overgrowth) and some functional gut disorders, eg bloating and diarrhoea, where no ‘disease’ is identified but symptoms persist.
Watch outs: It’s restrictive and not designed for long-term use. Without proper reintroduction, it can negatively impact gut microbiome diversity. Best followed with professional guidance to ensure gut health is supported throughout.
Ketogenic
What it is: A very low-carb, high-fat diet that switches the body into ketosis, where it burns fat for fuel instead of glucose. Originally developed for epilepsy management, it now has broader therapeutic applications.
What it’s great for: Neurological conditions like epilepsy and cognitive decline, managing chronic fatigue, blood sugar regulation and as adjunct support in metabolic disorders such as type 2 diabetes. It is also showing promise for supporting mental health and neurodivergent conditions such as ADHD. Early research suggests that by providing ketones as an alternative energy source for the brain, keto may help stabilise mood, focus and cognitive performance.
Watch outs: Can be nutrient-poor if not carefully planned. Long-term keto may not suit everyone and should be monitored.
Modified Mediterranean
What it is: A diet rich in olive oil, fish, vegetables, legumes, nuts and whole grains, with minimal processed foods and moderate dairy, meat and wine. The Med diet is known for its anti-inflammatory and heart-protective properties.
What it’s great for: Supporting cardiovascular health, managing type 2 diabetes and blood sugar balance, reducing risk of cognitive decline and lowering overall inflammation. It also promotes gut microbiome diversity thanks to its fibre and polyphenol content.
Watch outs: While flexible and sustainable, weight management still requires attention to portion sizes – especially with breads, pasta and wine. It’s a lifestyle, not a prescriptive “plan”, so some people need guidance to avoid slipping into too many refined carbs.
Anti-inflammatory diet
What it is: Less a formal diet, more a way of eating focused on reducing inflammatory triggers – emphasising colourful vegetables, omega-3-rich foods (like oily fish and flaxseed), nuts, seeds, herbs and spices (like turmeric), while limiting processed foods, sugar, refined carbs and trans fats.
What it’s great for: Managing chronic inflammatory conditions such as arthritis, skin issues (eczema, psoriasis), cardiovascular disease, autoimmune conditions and as supportive care alongside cancer treatment. Its focus on low glycaemic index (GI) foods, antioxidants and moderate healthy fats makes it a strong foundation for reducing systemic inflammation.
Watch outs: It can feel vague without professional input, as there’s no strict rulebook. Some people focus too much on “superfoods” without addressing hidden inflammatory triggers like stress, poor sleep, or food sensitivities.
DASH (Dietary Approaches to Stop Hypertension)
What it is: Originally developed to lower blood pressure, DASH focuses on fruits, vegetables, whole grains, lean proteins and low-fat dairy, while reducing sodium, red meat and processed foods.
What it’s great for: Clinically proven to reduce high blood pressure, support heart health and lower risk of stroke and kidney disease. It’s a balanced, sustainable approach for anyone managing cardiovascular risk factors.
Watch outs: Some versions still promote low-fat dairy and higher carbohydrate intake, which may not suit everyone, especially those with insulin resistance or type 2 diabetes. Sodium reduction should also be personalised – not everyone benefits from ultra-low salt diets.
Autoimmune protocol (AIP) / modified paleo
What it is: An elimination diet designed to reduce potential dietary triggers of autoimmune flare-ups. It removes grains, dairy, legumes, nightshades, eggs, nuts, seeds and processed foods, focusing on nutrient-dense meats, fish, vegetables (except nightshades) and healthy fats. After a period of elimination, foods are carefully reintroduced.
What it’s great for: Individuals with autoimmune conditions such as Hashimoto’s thyroiditis, rheumatoid arthritis, lupus or psoriasis who are looking to identify food triggers, reduce symptoms and support gut healing.
Watch outs: It’s highly restrictive in the elimination phase and not intended as a permanent diet. Without guidance, it can lead to nutritional gaps or an overly fearful relationship with food. Functional testing and personalised reintroduction phases are key to making it effective and sustainable.
Plant-based / whole food plant-based (WFPB)
What it is: A diet centred around unprocessed plant foods – vegetables, fruits, legumes, whole grains, nuts and seeds – while minimising or excluding animal products and processed foods.
What it’s great for: Supporting cardiovascular health, type 2 diabetes management, kidney health and reducing cancer risk. Rich in fibre, antioxidants and phytonutrients, it’s known for its role in chronic disease prevention.
Watch outs: Going plant-based doesn’t automatically mean healthy – ultra-processed vegan foods are still processed. Nutrients like B12, iron, omega-3 and zinc may require careful planning or supplementation.
A final note
These diets are powerful tools designed to manage or support specific health conditions – not trends to follow blindly. Many involve elimination phases, reintroductions, or nutrient focus that require expertise to get right. Used incorrectly, they can lead to nutritional gaps or make symptoms worse. If you’re considering a therapeutic diet, especially for gut health, autoimmune conditions, or chronic disease, work with a qualified professional to personalise the approach – and remember, food is just one part of the bigger picture.
