Can the CSN Diet Cause Gas?
More gas is common when you eat more fibre. Here is why, and what helps.
Yes, some people pass more gas when they start the CSN diet. More fibre from fruit, vegetables and whole grains gives the bacteria in your gut more to break down. For most people this settles as the body adjusts.
When to see a doctorIs passing gas healthy?
It’s nothing to be shy about: everyone passes gas. Gas comes from air you swallow and from the breakdown of food in your digestive tract. As with many health-focused diets, some people pass gas more often when they are on the CSN diet.
Most people pass gas 8 to 14 times a day, and up to 25 times a day is still considered normal, according to the US National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Some people pass more than others, which can be uncomfortable or embarrassing, but gas on its own is not a cause for alarm.
It can, however, be a sign of a digestive issue or of a change in diet. One of the easiest adjustments is a good balance of protein and plants, like fruit, vegetables and grains. These foods are all on the CSN food list, and they can cause gas in some people who have recently changed their diet.
What happens in your gut
Gas reaches your digestive tract in two ways: you swallow air, and bacteria in your large intestine break down carbohydrates that your stomach and small intestine could not digest.
- You eat more fibreCSN puts fruit, vegetables and whole grains at the centre of your plate.
- Some carbohydrates pass through undigestedYour body lacks the enzymes to fully digest certain complex carbohydrates.
- Bacteria in your large intestine ferment themThis produces gases such as hydrogen, carbon dioxide and methane.
Trapped gas can cause discomfort, from mild bloating to sharper pain, depending on where it builds up. For most people this is temporary as the body adjusts.
Habits matter too. Chewing gum, fizzy drinks and eating quickly all make you swallow extra air, which adds to the bloating from diet-related gas.
CSN foods that can cause gas
Fresh fruit and vegetables are staples of good nutrition, and CSN nutrition leans on them. The NIDDK lists fruit, cruciferous vegetables and legumes among the foods that can lead to extra gas, especially soon after you change your diet.
| Food group | Examples | Why it causes gas |
|---|---|---|
| Vegetables | Examples: Broccoli, cauliflower, cabbage, Brussels sprouts, asparagus | Why: They contain raffinose, a complex sugar that produces gas as gut bacteria break it down. They are very healthy, so think twice before removing them. |
| Fruit | Examples: Apples, peaches, pears, prunes | Why: Some fruits contain sorbitol and fibre, which bacteria in the large intestine break down into gas. |
| Legumes | Examples: Beans, peas, lentils | Why: High in raffinose, a sugar your body can’t fully break down before it reaches your gut bacteria. |
| Protein | Examples: Meat, protein powder supplements | Why: Eating more meat does not make you pass gas more often, but it can make the smell stronger. Some people find protein powders add to gas, possibly because of their non-protein ingredients. |
How to ease bloating while you adjust
Most of these habits come from NIDDK guidance. They help your body settle into a higher-fibre way of eating.
- Increase fibre gradually so your digestive system has time to adjust
- Start with small portions of the foods that tend to cause gas
- Drink more water: it helps fibre move through and eases constipation
- Eat smaller meals more often, rather than large ones
- Keep a food diary to find the foods that trigger your gas
- Avoid fizzy drinks and drinking through a straw
- Eat slowly, skip chewing gum and avoid talking while you eat, so you swallow less air
When to see a doctor
Talk to your doctor if gas bothers you, if your symptoms change suddenly, or if you also have stomach pain, constipation, diarrhoea or weight loss. If you have irritable bowel syndrome or another digestive condition, speak to your healthcare provider before changing your diet.
Frequently asked questions
What drink removes gas from the stomach?
Warm water, peppermint tea and ginger tea are commonly used to ease trapped gas. Fizzy drinks do the opposite and are best avoided.
What is the number one food that causes gas?
Beans and other legumes are usually named as the most common culprit, because they are high in raffinose, a sugar your body can’t fully break down before it reaches your gut bacteria. Cruciferous vegetables like broccoli and cabbage are close behind.
How can I reduce gas quickly?
There is no guaranteed instant fix. Gentle movement such as a short walk, a warm compress on your stomach, or a cup of peppermint or ginger tea can help some people feel better.
Sources: NIDDK, Symptoms and causes of gas, Eating, diet and nutrition for gas and Treatment for gas; Cleveland Clinic, Gas and gas pain. Last updated 28 September 2026.
Starting CSN and not sure what to eat?
Check the CSN food list, then build your meals from it one step at a time so your gut can adjust.