What are some healthy, low-calorie hamburger toppings?

 There are many healthy and low-calorie toppings you can add to a hamburger to make it more nutritious and flavorful. Here are some options:

1. Lettuce leaves: Instead of using a traditional bun, try wrapping your burger in large lettuce leaves, which are low in calories and rich in vitamins and minerals.

2. Tomatoes: Sliced tomatoes are a great addition to any burger. They are low in calories and provide a good dose of vitamin C and other nutrients.

3. Onions: Raw or cooked onions are a flavorful addition to a burger, and they're low in calories. Onions are also a good source of vitamin C and other nutrients.

4. Pickles: Pickles are low in calories and add a tangy flavor to a burger. They are also a good source of vitamin K and other nutrients.

5. Avocado: Adding sliced avocado to a burger can make it creamy and delicious. Avocados are high in healthy fats, fiber, and other nutrients.

6. Mushrooms: Sautéed or grilled mushrooms can add a meaty texture and umami flavor to a burger. They are also low in calories and a good source of B vitamins and other nutrients.

7. Bell peppers: Sliced bell peppers are a colorful and flavorful addition to a burger. They are low in calories and high in vitamin C and other nutrients.

Remember that portion control is also important when it comes to managing calorie intake. While these toppings are healthy, it's still important to watch how much you eat to maintain a balanced and healthy diet.