The truth is that most diets work. The most common reason they do not work is usually found in a person commitment or ability to sustain the changes for a long enough time for changes to take into affect. All nutrition advice given here, I still recommend consulting with a professional or someone that is certified to help monitor and make sure the diet is aligned with your goals.
A lot of fad diets follow along guidelines from other diets. When choosing a diet, I always recommend starting slow and making small behavioral changes in order to comply long term. The following diets are just some that you may run into. If you have questions, feel free to ask one of your coaches about their thoughts and if the diet fits your goals.
Low Calorie. The age old, calories in versus calories out diet. Burn more calories than you consume and your body will begin to use its fat stores for energy. The important thing here is finding out what you BMR is or basically how many calories your body burns in a day. From there, reducing approximately 500 calories per day can help reduce body mass. There are other factors at play here including, activity level. Also as not to go too low where starvation mode can actually set in. For men this is around 1500 cal and 1200 for women.
Low Fat Diet. This is where 20-30% of your diet is comprised of fat. The remaining 70-80% from protein and carbohydrates. Lowering your high calorie dense fat macro will help you lower calorie consumption overall. Studies have shown that this a quick way to lose weight but may be hard to sustain long term. Keep in mind that this diet is not meant to vilify the consumption of fat. Dietary Fat does not equal body fat or adipose tissue.
Low Carbohydrate Diet. This diet is defined as only getting 15-40% of your diet from carbs. The remaining from fat and protein. Benefits of this diet besides fat loss is lower risk of heart disease and stroke. When including an exercise regimen into this diet, one must also take a look at fueling their body based of what type of exercise they are doing, which is why low carb intake may still be around 40% of the total number of calories consumed. Some studies show that the high protein portion of this diet also help maintain and build muscle.