Boredom with a diet often comes in the form of food frustration. If you get bored with the food that you eat, you may start to avoid those foods in favor of other foods that are much higher in calories. I find that I can eat the exact same lunch and dinner foods for about 2 weeks before I get bored of them, but I've been eating the same breakfast for a year and a half and I still look forward to it every morning. It's helpful to have a menu with a variety of foods that you can eat - if you eat sandwiches for lunch, using different cheeses, meats, vegetables, breads, and other fillings can refresh your palate. Use provolone instead of cheddar, or tuna and hummus instead of a usual tuna salad, or pita instead of sliced bread. For salads, use different dressings, and add a variety of mix-ins like peppers and chickpeas. It's important to have a variety of textures and flavors in any diet. Brainstorm dinner options that you know are low in calories and plan one or two weeks' worth of meals when you go to the grocery store.