Your health ‘to do’ list for 2026 in 6 ‘easy-ish’ steps:

1. Reduce or exclude ultra-processed foods (UPFs). Spot them easily by learning the NOVA Food Classification system
2. Cut out artificial sweeteners and emulsifiers from your diet completely. This is actually pretty easy when you’ve made a few habit changes. You may need to spend a bit more on bread (or even better, bake your own) and stop drinking fizzy drinks (besides Coca-Cola – something I never thought I’d say but it’s the only one that now doesn’t include artificial sweeteners due to the UK government’s ridiculous, knee-jerk and short-sighted sugar tax!)
3. Increase your dietary fibre intake. This one is a bit more difficult as it will probably involve a big shift in diet, however, even a small change is better than no change. Many people add supplements like psyllium husks or inulin to quickly increase their fibre intake.
4. Cut down on saturated fats and completely cut out all trans fats. The easiest way to start moving in this direction is to cut down on (or even better completely cut out) red meat due to their saturated fat contents, and completely avoid all fried takeaway food. Look out for the words hydrogenated/shortening/vanaspati on food labels. Fried and cheap laminated baked items (like puff pastry or croissants – laminated is where there are layers of dough with fat between) have historically used shortenings or PHOs (partially hydrogenated oils). Street/restaurant foods are common sources of industrial TFAs (trans fatty acids)
5. Stop drinking alcohol, or cut down. Besides the disruption to the human gut microbiome, Alcohol is officially classified as a Group 1 Carcinogen – the highest classification, meaning there is “sufficient evidence” that alcohol causes cancer in humans, specifically linked to cancers of the mouth, throat, oesophagus, liver, breast, and bowel. 
6. Only use antibiotics if necessary. Always follow the medical advice including finishing the course if it’s been prescribed, but if they’re not absolutely necessary, I certainly would avoid taking them. Remember, anti-biotics only work against bacteria, not viruses. A few months ago I went to the pharmacy with a cold. I asked for something to reduce the symptoms as I had to work away for a week and the pharmacist tried to prescribe anti-biotics. Needless to say I declined.

That’s it – your 2026 and beyond New Year Resolutions for a healthier future

Based on current evidence, these foods or dietary patterns are associated with negative shifts in microbial diversity, composition, and function.

Category of Concern	Specific Foods/Ingredients	Proposed Mechanism of Harm
1. Ultra-Processed Foods (UPFs)	Mass-produced packaged snacks, sugary breakfast cereals, reconstituted meat products, instant noodles, ready meals.	Primary Driver. Low in fibre (which microbes need), high in refined carbs/sugars, unhealthy fats, and a cocktail of emulsifiers, artificial sweeteners, and other additives that may directly disrupt the mucus layer and microbial community.
2. Certain Food Additives (Especially Emulsifiers & Artificial Sweeteners)	Emulsifiers: Polysorbate 80 (E433), Carboxymethylcellulose/CMC (E466), Lecithin (E322 – in high, purified doses). Sweeteners: Aspartame (E951), Sucralose (E955), Saccharin (E954).	Emulsifiers: May degrade the protective mucus layer lining the gut, bringing bacteria closer to the intestinal wall, potentially triggering inflammation and dysbiosis (animal & in vitro studies). Sweeteners: May alter microbial composition, selectively promoting bacteria linked to glucose intolerance and inflammation (human & animal studies, but effects are highly individual).
3. Diets Chronically Low in Dietary Fibre	Typical “Western Diet”: High in refined grains, white bread, pasta, processed meats, and low in fruits, vegetables, legumes, and whole grains.	Starves beneficial microbes. Fibre is the primary fuel (prebiotic) for beneficial bacteria like Bifidobacteria and Faecalibacterium prausnitzii. Low fibre intake reduces microbial diversity and leads to a decline in beneficial short-chain fatty acid (SCFA) production, which is crucial for gut barrier health and anti-inflammation.
4. High Saturated & Trans Fat Diets	Fatty cuts of red/processed meat, fried foods, pastries, certain margarines.	May promote the growth of pro-inflammatory bacteria and bile-tolerant microbes like Bilophila wadsworthia, linked to increased gut permeability (“leaky gut”) and inflammation.
5. Excessive Alcohol	Heavy, chronic consumption of all types.	Disrupts the gut barrier, increases intestinal permeability, and alters microbiome composition, often reducing beneficial bacteria. Associated with dysbiosis in conditions like alcoholic liver disease.
6. Antibiotics (Not a food, but critical context)	Non-judicious use in medicine and agriculture (entering food chain).	The most potent disruptor. Broad-spectrum antibiotics act like a “forest fire” in the gut, indiscriminately killing both harmful and beneficial bacteria. Recovery can take months or years, and some species may be lost permanently.

Key Takeaways & Nuances:

• Individuality is Paramount: The microbiome’s response to foods like artificial sweeteners or fats can vary dramatically between individuals, based on their unique baseline microbiome (a key finding from Elinav’s and Spector’s work).
• The “Matrix” Matters: An emulsifier in a fibre-rich, whole-food smoothie may have a different effect than the same emulsifier in a sugary, fibre-free drink. The overall dietary pattern is more important than any single ingredient in isolation.
• Dose and Duration: Occasional consumption is unlikely to cause lasting damage in a healthy person with a diverse diet. The primary concern is chronic, high-level consumption of the low-fibre, additive-rich UPF diet.
• Beneficial Foods: To counteract these concerns, the consensus is to prioritise a high-fibre, diverse, predominantly plant-based diet. This includes fruits, vegetables, legumes, whole grains, nuts, seeds, and fermented foods (like live yoghurt, kefir, kimchi, sauerkraut), which provide probiotics and support microbial diversity.

In summary, the greatest threat to the gut microbiome is not one “villain” food, but the chronic consumption of the low-fibre, high-UPF “Western Diet,” which deprives beneficial microbes of their needed fuel while exposing them to potentially disruptive additives. The work of the experts listed above continues to unravel the intricate details of this relationship.

The field of research into the human gut microbiome is collaborative, but these individuals and their institutions are widely recognised as leaders. Experts often specialise in specific areas: ecology, immunology, nutrition, or biotechnology.

Current influential researchers on the human gut microbiome:

1. Prof. Rob Knight (University of California, San Diego, USA)
   • Why an expert: A true pioneer in microbial ecology and bioinformatics. Co-founded the American Gut Project and the Earth Microbiome Project. His lab develops the computational tools used to analyse microbiome data globally.
   • Focus: Mapping the microbiome across environments and human populations, its development from birth, and its links to a vast range of diseases.
2. Prof. Tim Spector (King’s College London, UK)
   • Why an expert: A leading figure in making microbiome science accessible. Founder of the British Gut Project and the PREDICT studies (the world’s largest ongoing nutritional research programme). Focuses on diet, twins, and personalised responses to food.
   • Focus: Diet-microbiome interactions, personalised nutrition, and the role of diversity. His book Spoon-Fed is highly influential.
3. Prof. Eran Elinav (Weizmann Institute of Science, Israel)
   • Why an expert: Heads a world-leading lab known for rigorous, groundbreaking science. His work has fundamentally changed how we view personalised responses to food and artificial sweeteners.
   • Focus: Host-microbiome interactions in nutrition, cancer, and the immune system. Famously demonstrated how artificial sweeteners can induce glucose intolerance via the microbiome in Nature (2014).
4. Prof. Jeffery I. Gordon (Washington University in St. Louis, USA)
   • Why an expert: Considered the “father of the human gut microbiome.” His lab was the first to show the direct causal role of gut microbes in obesity using germ-free mouse experiments.
   • Focus: Microbiome development in childhood malnutrition (pivotal work on “microbiota-directed complementary foods”), and energy harvest from diet.
5. Prof. Sarkis K. Mazmanian (California Institute of Technology, USA)
   • Why an expert: A leader in exploring the microbiome-gut-brain axis and its role in neurological conditions.
   • Focus: How gut microbes influence the immune and nervous systems, particularly in Parkinson’s disease and autism spectrum disorders.
6. Dr. Joël Doré (INRAE, France)
   • Why an expert: A leading European researcher focused on microbial ecology and the functional core of a healthy human microbiome.
   • Focus: Defining what constitutes a “healthy” microbiome and its resilience. Significant work on probiotics and prebiotics.

Key Institutions & Resources:

• The Gut Microbiota for Health (GMFH) platform: A major knowledge hub curated by the European Society of Neurogastroenterology & Motility (ESNM).
• The Human Microbiome Project (NIH, USA): The foundational large-scale project that catalysed the field.
• The ZOE Project (UK/US): Co-founded by Tim Spector, this large-scale study powers the ZOE personalised nutrition app and produces high-impact research on diet and microbiome.