Will that make you gain weight if you don't eat the recommended amount of calorie intake while losing weight?

Maybe: If you constantly eat too little your body can go into a survival mode thinking that food is not avialble and reduce your metabolism. Generally when on a weightloss program, the set calories are an average per day (you may go over one day & under one) but try to stay close to the suggested amount so your body does not think it is being starved.