WILL I LOSE WEIGHT BY DOING THIS?

i am going to the gym between 4-7 times a week and burning around 600-800 calories each time. my diet consists of cornflakes for breakfast, for lunch i either have spagetti in tomato sauce with toast or a sandwich with crisps and an orange and a yoghurt. for dinner i have quorn or tuna with a chile con carne sauce with either brown pasta or brown rice with mixed vegetables (peas, carrots, sweetcorn)