Low fat foods may seem like a healthy option, but when fat is taken out food companies often add fillers and sugars to make the product taste normal. Low fat yogurt is an example of a diet food with very little nutritional value. For a more nutritious option, look for true yogurt that contains milk and cultured enzymes.
Salad is one of the most popular diet foods, but what goes on top of the salad can very easily make it unhealthy. Many salad dressings can be high in calories, contain rancid oils, high fructose corn syrup, and MSGs. Do not be fooled by diet dressings, as they are also usually unhealthy. The best option is to make dressing at home by mixing high quality olive oil and balsamic.
Granola is a healthy food, but it is often prepared in a way that is not conducive to weight loss. Check the ingredients for sugar and rancid oils. Healthy granola bars do exist, but finding them requires reading the packaging to find out what goes in the bar.
Being gluten-free is a huge trend right now and has helped many people live a healthier lifestyle, but not all gluten free products are good for weight loss. Gluten free junk food is still junk food and eating it will cause weight gain.