Flatulence is completely normal and part of the healthy digestive process. Those who meet their recommended intake of 30g of fibre pass wind between 10 and 20 times a day – it is a sign of a well-fed gut microbiome! However, if your flatulence becomes excessive or the smell is causing a problem then there are things you can do to help manage it.

Gas is formed in two ways; from the air that we breathe in and as a by-product of our gut microbiome fermenting (eating) leftover food in our intestines. In healthy individuals, 70% of this gas production is produced by our gut microbes.

Excess gas can be due to excess fermentation by your gut bacteria, which may mean you’ve overfed your gut microbiome. There are several causes for excess fermentation –

  1. Excess food residue – the more food that reaches the large intestines, the more fermentation will occur! Excess food residue can be caused by food travelling too fast through the small intestines, food intolerances, a very high fibre diet or if you rapidly increase your fibre intake.
  2. Constipation – when things move slowly through the intestines, your gut bacteria get more time to ferment the leftover food that would otherwise have exited in your poop.
  3. Small intestinal bowel overgrowth (SIBO) – when a considerable number of bacteria travel up from the large intestines into the small intestines (SIBO), these bacteria ferment the food that they may not have had access to in the large intestines.

99% of the gas produced by our gut microbiome including hydrogen, methane and carbon dioxide, is odourless. So why does flatulence smell? 

The smell is coming from the bacteria breaking down sulphur-contain compounds in our diet. This produces trace amounts of sulphur-containing gases such as hydrogen sulphide.

Foods and/or drinks that are high in sulphur-containing compounds include those high in specific amino acids. These include protein supplements, meat, chicken, eggs. Sulphur-containing compounds are also found in cruciferous vegetables (e.g. broccoli, cauliflower, cabbage, kale, Brussel sprouts, turnips), allium vegetables (e.g. onion, garlic, leeks and chives) and additives (e.g. some beer and wine).

This doesn’t mean that you should be cutting out these vegetables from your diet as they contain several health benefits and excessive protein intake is often a bigger factor to odour. 

Managing flatulence

If you are also suffering from constipation, it is important to address this first and this should help address the flatulence. For more information, read our article on managing constipation.

If you are struggling with excess gas without constipation, then you can try the following interventions –

Excess gas

  • Keep a food and symptom diary to identify any foods you may be intolerant to. Try reducing the intake of these food/food groups and monitor your symptoms.
  • Avoid added polyols, these are commonly found in sugar-free foods and chewing gum. These sweeteners are hard for your small intestine to absorb and leads to bacteria feasting, causing excess gas
  • Reduce your intake of high FODMAP foods, for a list of FODMAP foods check out this article. It is important not to cut out all FODMAP foods from our diet without a healthcare professional as this can starve your gut microbiome, but it may help ease your symptoms and identify any foods you are more sensitive to.
  • An imbalance in your gut microbiome, an increase in pathogenic bacteria and decrease in beneficial bacteria, can result in an overproduction of gas. Friendly bacteria supplements can help balance the gut microbiome and reduce gas production.
  • Try peppermint oil capsules. The oil is an anti-spasmodic and relaxes the gut. This can be used as symptom relief however shouldn’t be used as a long-term treatment.


  • If you’re eating large portions of protein, e.g. supplements or large amounts of animal sources, consider decreasing your protein intake. If you don’t want to decrease your protein intake, research has also shown that increasing fibre intake may help manage odour as your gut microbes are kept busy by dietary fibre and have less time to ferment sulphur-containing amino acids found in high-protein foods.
  • Reduce your intake of sulphur containing vegetables and alcohol. You may find that you can tolerate a certain amount of certain vegetables without having to cut them out.

If you'd like to learn more about flatulence, why not book a free 1:1 consultation with our nutrition team? We can recommend diet and lifestyle changes that can make a big difference. To book, simply click here.