what happeneds to your body when you eat any fast food once a week?

my husband is aready over weight and his tryglisorides is at 220 we are in a weight loss group but i dont think he takes it seriouly and i am concern... for me i do take it seriouly he is 5"8 large bone and stocky he is currently weight 216 he needs to be at least 190 and most of his weight is in his gut plus other places. i try to support him and let him know thats not the best choise for healthy eating just last night he went to burger king and ate the double wopper with cheese combo with large fries and a med coke minus the mayo,the pickes, and lettce. and i wanted to save money. so i said i rather go home and make a healthy dinner and he tells i can help it i want something bad. thats were i get frusterated. my husband is 44 and iam 39 heart problems runs in both our familys and so do the tryglisoreds. any advised what to do ? as for me iam 5"5 med bone and at 150