Why the gut matters in metabolic health

Managing high blood sugar, cholesterol and blood pressure have been at the heart of treatment of metabolic diseases such as obesity and type 2 diabetes. However, research now suggests the gut microbiome is also critical to good metabolic health. The microbes in our guts influence how we regulate blood sugar, store fat, control appetite, and manage inflammation.

The microbiome therefore acts as a central regulator of energy balance, inflammation, and metabolic signalling. When the gut microbiome becomes imbalanced (a state known as dysbiosis), it can contribute to metabolic problems such as insulin resistance, high cholesterol, and weight gain.

Here we describe practical steps you can take to improve metabolic health by focusing on the health of your gut microbiota.

Why gut health matters for metabolic health

The gut microbiome communicates constantly with the rest of the body through several biological pathways. Research shows it can influence metabolism through the gut–brain axis, gut–liver axis, immune system, and hormonal signalling pathways.

When the microbiome is healthy and diverse, it helps maintain metabolic balance. When it becomes disrupted, these regulatory systems can malfunction.

Several key mechanisms explain how the gut matters for metabolic health:

1. Gut bacteria produce metabolic signals

Gut bacteria ferment certain types of dietary fibre — known as prebiotics — into beneficial molecules called short-chain fatty acids (SCFAs) such as acetate, propionate and butyrate.

These compounds act as powerful metabolic messengers in the body.

SCFAs can:

• Improve insulin sensitivity

• Help regulate blood sugar

• Reduce inflammation

• Increase production of hormones that promote satiety

2. The gut barrier protects metabolic health

The lining of the intestine acts as a barrier between the gut and the bloodstream. When this barrier becomes weakened — sometimes described as increased intestinal permeability — inflammatory molecules from bacteria can enter circulation.

These include substances such as lipopolysaccharides (LPS), which can trigger inflammation in the liver and throughout the body.

This process can contribute to:

• Insulin resistance

• Fatty liver disease

• Chronic low-grade inflammation

Prebiotic fibres help strengthen this barrier by supporting bacteria that produce butyrate, a key energy source for intestinal cells.

3. The gut influences hormones that control appetite

The gut microbiome also interacts with hormone systems that regulate hunger and metabolism. For example, SCFAs stimulate gut cells to release hormones such as GLP-1 and PYY, which help regulate appetite and glucose metabolism.

This means that the bacteria in the gut can directly influence how hungry we feel and how efficiently we process food.

These hormones slow gastric emptying, improve insulin secretion, and increase feelings of fullness after meals.

When gut microbes are disrupted, these signals can become impaired, contributing to overeating and poor blood sugar control.

4. Gut microbes affect lipid metabolism

The microbiome also plays a role in how the body processes fats and cholesterol. Research shows that beneficial gut microbes can:

• Improve lipid metabolism

• Reduce triglycerides and LDL cholesterol

• Influence bile acid metabolism in the liver

These effects help protect against conditions such as cardiovascular disease and metabolic syndrome.

Signs your gut health may be affecting metabolism

Gut dysfunction linked to metabolic problems may present with symptoms such as:

• Persistent fatigue after meals

• Sugar cravings

• Difficulty losing weight

• Bloating or digestive discomfort

• Elevated triglycerides or insulin resistance

While these symptoms can have many causes, improving gut health often improves metabolic markers at the same time.

Dietary strategies to improve gut and metabolic health

The encouraging news is that diet is one of the most powerful ways to influence the gut microbiome.

The goal is to feed beneficial microbes while reducing factors that disrupt microbial balance.

1. Increase prebiotic fibre

Prebiotics are specific fibres that beneficial gut bacteria ferment into SCFAs. Examples include:

• Onions

• Garlic

• Leeks

• Asparagus

• Chicory root

• Jerusalem artichokes

• Beans and lentils

• Resistant starch, which is found in foods such as green bananas and raw potato starch

  
  

These fibres support microbial diversity and help regulate metabolic pathways involved in glucose and lipid metabolism.

2. Include fermented foods

Fermented foods introduce beneficial microbes and microbial metabolites into the gut. Examples include:

• Natural yogurt

• Kefir

• Sauerkraut

• Kimchi

• Miso

• Tempeh

These foods can support microbial balance and reduce inflammation.

3. Eat a diverse range of plant foods

Microbial diversity is strongly influenced by dietary diversity.

Aim for 30 or more different plant foods per week, including:

• Vegetables

• Fruits

• Herbs

• Nuts

• Seeds

  
  

Try to eat a wide range of different coloured fruit and vegetables, covering all the colours of the rainbow.This provides a wide range of fibres and polyphenols that feed different microbial species.

4. Include polyphenol-rich foods

Polyphenols are plant compounds that also act as microbiome modulators. Good sources include:

• Berries

• Dark chocolate

• Green tea

• Olive oil

• Red grapes

• Cocoa

These compounds support beneficial bacteria while suppressing potentially harmful microbes.

5. Avoid ultra-processed foods

Diets high in refined sugars, processed fats, and additives can disrupt the microbiome and promote dysbiosis.

Reducing these foods can help restore microbial balance and reduce metabolic inflammation.

The bigger picture: gut health as a metabolic strategy

Research now shows that the gut microbiome may act as a central regulator of energy balance, inflammation, and metabolic signalling. Supporting gut health through diet can help address several aspects of metabolic dysfunction. Improving gut health through dietary diversity, fibre intake, and whole foods represents a practical and low-risk strategy to support long-term metabolic wellbeing.

Key references

Chalotra R, Gupta T, Kumar A, Gupta A, Kumar S, Singh TG, Singh R. Prebiotics, Probiotics, and Postbiotics in Modulating Gut Microbiota: Emerging Therapeutic Approaches for Metabolic Syndrome. Curr Obes Rep. 2026 Feb 9;15(1):9. doi: 10.1007/s13679-026-00686-8. PMID: 41661460.

Blaak E.E, et al. Short chain fatty acids in human gut and metabolic health. Benef Microbes. 2020 Sep 1;11(5):411-455. doi: 10.3920/BM2020.0057. Epub 2020 Aug 31. PMID: 32865024.

Tolhurst, G, et al. Short-chain fatty acids stimulate glucagon-like peptide-1 secretion via the G-protein-coupled receptor FFAR2. Diabetes. 2012 Feb;61(2):364-71. doi: 10.2337/db11-1019. Epub 2011 Dec 21. PMID: 22190648; PMCID: PMC3266401.

Facchin S, et al Short-Chain Fatty Acids and Human Health: From Metabolic Pathways to Current Therapeutic Implications. Life (Basel). 2024 Apr 26;14(5):559. doi: 10.3390/life14050559. PMID: 38792581; PMCID: PMC11122327.

Deehan, E.C., Mocanu, V. & Madsen, K.L. Effects of dietary fibre on metabolic health and obesity. Nat Rev Gastroenterol Hepatol 21, 301–318 (2024). https://www.nature.com/articles/s41575-023-00891-z#citeass://doi.org/10.1038/s41575-023-00891-z