This is your first important step to successful weight-loss, and the best way to achieve your target weight.
Complete the diet diary for at least 2 weeks, so you can discover your eating habits. You'll soon see when in the day you are most hungry, and what makes you reach for quick-fix snacks. Armed with this information you'll be able to predict when you need to have healthy food alternatives ready, or places or situations to avoid while you are dieting.
Good luck, and most importantly, be honest - only you need read your diet diary.