There are a few reasons why hiking might suppress your appetite. First, hiking can lead to increased levels of endorphins, which are hormones that block pain signals from the brain and make you feel good. This could lead to an overall feeling of satisfaction and reduced hunger pangs. Additionally, walking or hiking uphill may cause your body to burn more calories than if you were walking or hiking downhill, since your muscles have to work harder in order for you to maintain balance. Finally, spending time outdoors in nature has been shown to boost moods and reduce stress levels, both of which could help reduce cravings for unhealthy foods.