If you're being told that dieting and exercise works, then you've been told a lie.
Yup I said it! Exercise and dieting does not work.
"Mark you're a trainer and you're telling me this! What is this nonsense?!" Lets keep reading...
If you believe that dieting for a summer bod is sustainable for longevity, then you need to completely dismiss that from your belief system. You now have to take a different approach.
Exercise and proper nutrition will "work" only if YOU are putting in the effort. How far are you willing to go to stick to a structured program that will improve your agility, mobility, and strength. This does not apply to playing a sport. Do you enjoy dancing? Do you enjoy playing outdoors? Do you enjoy playing with your pets? Do you value playtime with your kids, nieces, nephews, or grand children. If so, then you have to maintain proper function of the unique machine that you were blessed with: your body.
How to do you maintain your body? Just like a car, you have to have frequent services. This will allow your car to drive smoothly, efficiently and safely. In regards of your body, these services come in the form of consuming whole nutrition on a daily basis, working out in a way that puts a demand on your physiological functions. If you want to improve your health you need to do things that work FOR your health, not against your health. If you want to increase your strength then you need to work against resistance. If you want to increase your energy, then stop looking externally and look at what is going into your body. In other words, start from the inside.
So of course, exercise and dieting doesn't work. It'll only work if YOU work. But the point of exercise is to optimize, or at least, maintain your health and body. This will allow for a better quality of life.
When you live a great life, your energy will rub off on those around you. You will no longer need to wear a mask and hide behind pain or insecurities because you've created a love for yourself. A love that allows you to stay consistent with fueling your body with whole nutrition and using your body to move in a way it was designed to do.