Can laxitives help you lose weight if you take it with food?

No, this is a very dangerous thing to do. Laxatives should only be used if you are having bowel problems. Over using them can cause serious problems like

severe "bloating, cramping, dehydration, electrolyte disturbances and imbalances, cardiac arrhythmias, irregular heart beat and heart attack, renal problems, and death."

It's never a good idea to take laxatives like this. Your body will pass the food naturally. Instead of this, gradually moderate the amount you eat and cut out fats etc.