insanity

You can, if you have the energy to do so. Insanity is designed so that you give 100% of what you are physically able to at all times. You have to push yourself to your absolute limits during every workout. This is why Insanity works so well and so fast. I'm in Week 5 of Insanity, and I can't imagine taking on any other workouts while doing this. Insanity alone is an amazing workout and you really don't need much else if you're doing it right (if you are trying to lose weight). Although, maybe if you did one workout in the morning and one in the evening on those days... When I started out, I couldn't even walk the next day, let alone think about going to the gym and lifting. Just listen to your body. If you over-do it, then you are more susceptible to injury.
I've lost 15 lbs since I started Insanity 5 weeks ago, hoping to drop another 15-20 in Month 2.

I've been sticking to 1500-1800 calories per day (intake), spread out over several small meals/snacks.

I start my day with a glass of green tea and either a banana or 100 cal. granola bar. I have several 100 cal. snacks that I take to work with me (granola bars, low fat/low sodium pretzels, etc...) - I eat one about every 2 hours. I typically add a protein supplement (either a shake or protein bar) around noon to help curb my hunger around my typical "lunch" time.

I have a normal dinner - whatever the family is having for the night. That may include pizza, or tacos, or mac & cheese, or sometimes some healthier options - just whatever is being cooked for the night. This way I don't have to cut out the foods that I like, I just limit the portions that I eat to stay within my calorie goals for the day.

I do my workouts in the evening about 3-4 hours after dinner, then have another protein shake after my workout.

I allow myself one "cheat" (or reward) meal every other week. This is when we typically go to one of our favorite restaurants. My calories normally exceed my daily goal on these days.

You'll hear a lot of varying opinions on what and how you should eat, and whether or not cheat meals are good or bad, etc...

Here is my opinion on the subject: Eating several small meals throughout the day allows your metabolism to remain consistent and allows calories to be burned in a consistent manner. Your body doesn't feel the need to store any resources as fat, because you are consistently providing it nourishment throughout the day. The mid-day protein supplement is beneficial because protein is more filling than carbohydrates and you will feel full longer. Also, I have a really good chocolate shake that I actually enjoy, so it helps curb any cravings I have for sweets. Protein after workouts is very important to allow your body to absorb and use the protein it needs for the muscles to recover. Cheat meals are also important if you are trying to lose weight. A cheat meal "shocks" your body and can actually boost your metabolism. If you stick to a 1500-1800 calorie diet, then your body will get used to being provided that amount of calories. By adding in strategic cheat meals into your diet plan (I do bi-weekly), your metabolism will go up significantly when you go over your typical amount of calories for the day. Then when you return to eating your typical 1500-1800 calorie diet, your metabolism will remain higher for a period of time. This is also a good way to overcome a plateau.

Again, this is only my opinion. I have done a lot of research, but I am in no way a professional in the field, so take it with a grain of salt, as you should with a lot of advice on public forums. Many people may say that I'm wrong on this, but they are also entitled to their opinions. All I know, is that my brother lost 120 lbs. in 9 months following this exact plan. So, I've seen it work. I'm not trying to lose 120 lbs, but if I could lose a total of 40 in a short period of time, I'll be very happy!

Best of luck to you!!

It's totally do-able. It all depends on how hard you work at it. You can do it!!