Unfortunately, dietary changes alone are not effective in relieving IBS symptoms in everyone. There is great evidence that for many sufferers, that a low FODMAP diet can help relieve the symptoms. FODMAP foods are carbohydrates that ferment in your gut eg. wheat, onion, garlic, dairy and some fruits and vegetables.
Sometimes even identifying certain food sensitivities and allergies eg. potato or egg sensitivities can lead to a huge reduction in day to day management of the condition. If you suspect that certain foods might be making you feel worse, you could be right.