your workout wont do **** to loose weight if your diet sucks ass. as long as your are lifting hard i wouldnt worry about it at all. for the record, many 4 day programs lift mon, tues, thurs, fri. some do sun, mon, wed, fri. it makes no difference at all for 99.9999% of the worlds population. just do the days that you can and will workout on.
back to the diet part, so you are asking if you should eat more to shed weight? that seems kind of ass backwards. there are some programs you can google search and do. things like lean gains (an intermittent fasting variation) or carb backloading or carb cycling.
or you can follow these simple tips:
-avoid carbs in any form for the first meal of the day
-minimize carbs for all meals except post workout then feel free to indulge
-eat fatty meats. you still need calories and fat is ok. it does not make you fat like the media has been trying to convince you of your entire life