Excess protein consumption can increase body odor due to increased ammonia. Therefore, cutting back on meats in particular can help in some cases.
Supplementing with zinc, 50mg daily, can also help with controlling body odor. Make sure to take zinc after larger meals to prevent nausea.
You can also try digestive bitters to help the liver detoxify compounds more efficiently.
And drink plenty of water throughout the day. Avoid drinks such as coffee or colas, which dehydrate you.