The good news is that you can achieve virtually 100% of your fitness, body composition, and health related goals by avoiding extremes, including fad diet and exercise plans. They do not work. Some keys to looking, feeling, and performing your best for the long term include: a) lifting heavier weights, b) sprinting at a faster pace (or performing more reps of the sprint), or performing HIIT at a higher intensity (higher level, less rest intervals and/or longer work intervals), or c) performing exercises that are more challenging (possibly progressions of your current exercises), or d) improving your form in all of your exercises, or e) developing a healthy lifestyle that is enjoyable, practical, reasonable, and sustainable, and last but not least f) making sure that you get enough rest, and leisure time.
Obsessing about what you look like or how much you weigh, and performing the same monotonous workouts again and again (very often steady and boring cardio, or light weights with effortless high reps so you won't get ''bulky,'' or running yourself ragged, will not get you excited to work out, especially since you won't see or feel many, if any results. Chances are, you will feel physically and mentally drained, frustrated, bored, and highly unmotivated, which will make consistency and sustainability extremely challenging. This often leads MANY people to quit, and to jump back to their old and unhealthy ways.
Your healthy lifestyle should leave you feeling excited, empowered, energized, stronger and fitter, and incredibly motivated. Motivation + enjoyment + empowerment + moderation + energy = sustainability. Do whatever it takes to make YOU feel motivated, energized, and empowered.
There is no one size fits all approach, but I find that treating my workouts like I am competing in a sport and enjoying the process, and consuming healthy yet very enjoyable foods and treating myself in moderation, is highly effective and effortless. Give it a try.