Your diet is a critical part of everything and is also important in managing stress. One of the foods that I recommend is actually a multi-grain carbohydrate, multi-grain bread. What this does is, allows your body to metabolize sugars in a much more stable way, so you don't get those fluctuations and sugar in your body that can actually make stress worse.
There are some release of serotonin and the feel good hormone when you eat these multi-grain carbohydrates, and those can also be very, very helpful. Another thing is spinach for example, foods that are high in magnesium. What these food can do is decrease your heart rate, and actually stabilize things making you feel a little bit common.
Foods that are high in anti-oxidants like blue berries, dark chocolate, these kind of foods have something called polyphenols in them, and what they do is dilate the arteries and actually can decrease your blood pressure. So these are some choices of foods that can actually help with stress and then a little tip, if you are going to snack, try nuts.
Nuts are probably the best snacking food you can really count on, but go for pistachios, because every time you have to open one of those nuts, it will slow you down and that way you might not eat too many.