As weight-loss foods go, the ham sandwich isn't the worst choice. It's higher in calories and fat than some other options, but it has the protein and fiber to be more satisfying, and it can stand in as a fairly balanced main meal. If you eat ham sandwiches occasionally as part of a reduced-calorie diet, you may be able to drop a couple of pounds per week, but the sandwiches can't do all the work.
The U.S. Department of Agriculture reports that a ham-and-cheese sandwich contains about 350 calories, 21 g of protein, 15.5 g of fat (6.5 g of which are saturated), 60 mg of cholesterol and 33 g of carbohydrates. Specific nutrition facts depend on the ingredients you use for your sandwich. For example, whole-wheat bread is a healthier choice than white because it contains more fiber, which can help keep you fuller for a longer time. Using just a few slices of ham will yield a sandwich that is lower in calories and fat, and skipping high-fat add-ons like mayonnaise and cheddar cheese will also make the sandwich a better weight-loss food.
Eating a specific food cannot make you lose weight. To slim down, you must consistently burn more calories than you eat, regardless of the foods you choose. Thus, the amount of weight ham sandwiches can help you lose depends on the number of total calories you eat each day. If you usually eat about 700 calories per meal and you replace one meal a day with a 350-calorie ham sandwich, you'll build up a weekly calorie deficit of about 2,500, which will help you lose approximately 1 1/2 lbs. every two weeks.
The way you prepare your ham sandwich, its size and what you put in it all make a difference in its final calorie count and how useful it will be in a weight-loss plan. Along with using moderate amounts of meat and picking whole-grain bread instead of white bread, it's smart to eat just a half sandwich at a time. If that isn't enough to fill you up, supplement the meal with low-calorie accompaniments such as a fresh piece of fruit, veggie sticks or a cup of vegetable soup, all of which are likely to have fewer calories and less fat than the other half of the sandwich.
Talk with your doctor before you use ham sandwiches as a weight-loss tactic or make any big changes to the way you normally eat. The most effective weight-loss diets tend to include a balance of foods from all major groups, including whole grains, lean proteins, fruits, vegetables and low-fat dairy, the MedlinePlus online medical encyclopedia notes, rather than relying too heavily on any one type of food.