If you're the kind who always says yes, learn when it's time to decline. Keep a smile on your face. Learn new skills. The antidote to worry about losing your job is to make yourself all the more valuable. Manage your weight.
Stress can lead to overeating, and being overweight is stressful.
Don't eat for relief. Negotiate your work environment. Stress can come from noise, an uncomfortable chair, or poor lighting. Ask for improvements. Pet your pet.