Starving won't make you die so easily, it will take two months, maybe more (hard to say from people to people) . After few days you won't feel hungry anymore, but you will seriously decrease in energy, being tired and need to keep laying. If you have equipement, alright, but then? Just waiting in your tent?
About deshydration it's much faster but it's also painful. It's probably about a week, minimum once again hard to say depending the person and the location). After 2-3 days you won't feel fine, you could have headache, fever, nauseam. It could get worst After that because your main organs will began to suffer seriously.
In the tribal life some were doing so, like some animals do too. But understand they were doing that at the end of their life, when their body was already dying. They just felt the thing, talking their responsabilités and seek lonelyness for the last moment.
You are in a total different situation. You're in healthy condition not at the end your life; we're not used to this ancient rythm of life, we Come from the modern World. You're not an old native american chief, or an old tibetan monk...
Water is the essence of all life on earth. Deprive yourself of water will be hard, painful. I won't be surprised you will Come back after few days max in Bad condition. Forcing you to stay in the forest will be very challenging.