Below are some simplified dos and don'ts for getting in shape based on my experience:
DON'T get on a scale. DO look in the mirror and use a tape measure.
Reason: the scale is meaningless. You can lose 10 pounds of fat, gain 10 pounds of muscle and you will look and feel amazing but the scale will not tell you that! The only thing the scale might do is discourage you from staying the course if it doesn't tell you what you think you want it to.
DON'T try to be skinnier or thinner. DO try to be stronger.
Reason: Skinny is not healthy, period. The mindset should be to become a healthier, stronger, more flexible and just a more functional human being. This mindset will serve you well in the long run as we all inevitably have to fight the effects of aging (decreased muscle mass, decreased bone density, etc). Get strong now, while it's still easy!
DON'T excessively cut calories or carbohydrates. DO eat as much nutrient-dense food as you crave.
Reason: Cutting calories for too long will slow your metabolism down as you will go into "starvation mode". You will hold onto every last fat cell that is on your body and you can jack up your hormones. Your body is smarter than you are - don't fight it, work with it. Also, extended bouts of calorie restriction and ketosis are highly STRESSFUL to the body. High stress -> high cortisol -> fat storage. Instead, eat as many highly nutritious foods as you possibly can. Eat modest amounts of healthy "slow-digesting carbs" like brown rice, beans, sweet potatoes and yams. Give your body the fuel it needs to get through your workouts and to build that muscle so you can get stronger!
Jelly donuts do not count as “nutrient dense”
DON'T skip breakfast. DO eat 30 grams of high quality protein within 30 minutes of waking.
Reason: Intermittent fasting works for some but fasting is an added stress to the body. Have a high-paced job? Kids? Financial concerns? Exercise much? All of these are sources of stress - unless you have your stress management completely dialed-in, skip the fasting and have some high quality protein for breakfast.
DON'T over-train. DO listen to your body.
Reason: Exercise is a stress - and it is possible to overdo it, especially if you don't get enough sleep or adequate nutrition. If you feel crappy one day, it's ok to take the day off and/or go easier at the gym. Of course, if you feel great, you should seize the opportunity and make the trip to the gym count.
DON'T view exercise as just another chore. DO view it as a welcome break to the day and DO try to find ways to make it fun.
Reason: This is the key to making this part of a healthy, active lifestyle - include your family and friends when you can: hikes, walks, bike rides, etc. They need the motivation too sometimes so they will welcome your help!
DON'T go the gym without a plan. DO decide on routine and then stick to it.
Reason: I see this all the time in the gym. People wandering around aimlessly, trying to figure out what machine to do next. This melancholy mindset yields mediocre results and short unproductive time at the gym. But if you go there, already knowing that you are going to 4 sets of A, 3 sets of B, 3 sets of C, etc - you will get the most of the time you spend there.
These girls go to the gym with a plan.
DON'T get stuck in the same old routine. DO try new things.
Reason: Variation keeps the body guessing and keeps things fun and interesting.
DON'T worry if you don't follow tips 1-8 perfectly and/or if you have a few days off. DO realize each and every day is a new opportunity to do something great. :)