Cutting way back on calories is definitely detrimental. The key is making the most of the calories, using the right foods for fuel, and hitting macros.
I'm no expert, but since January I've read and read and read... and experimented like crazy. I swear, when I was 27 I lost 17 pounds and then I thought it was hard. It was EASY compared to how hard it is now at 41. But it made me step up and really look at my lifestyle, and make serious changes.
I'm not familiar at all with thyroid issues and diabetes, so I would never want to give bad advice. I'll tell you, though... I'll share what I do, and what it's done.
In January, I was 140+ lbs, drinking wine or beer about four nights a week, eating whatever I wanted. I'd try to "eat healthy" by frozen Lean Cuisine and the occasional salad, and then hit the gym three times a week to do 30 to 40 mins of constant, low intensity cardio. I was gaining weight - rapidly. So I began to research.
First, I learned the difference between weight training and cardio. Weight training burns more fat and calories than cardio ever will. It will NOT bulk you up. It builds muscle. Muscle burns fat. So... cardio will make you burn some calories while you are doing it, but weight training causes more calories burned over a way longer period of time. It's just a no brainer. WIN WIN WIN. Now... I love my ARC machine. I still do cardio, but I maximize my time and benefits with it. That low/medium intensity long period of time crap - is a total WASTE. Instead, I now do about 15-20 minutes of HIIT (high intensity interval training). Two minutes of warm up, then set that sucker up high and go hard and fast for as long as I can. Get that heart rate way up. Then stop, and go low setting and cool off for a minute or two. Then back up... over and over again. 20 minutes should be totally sufficient for cardio if you do it right.
Weights... I lift. I don't fuck around. I use free weights, rarely machines. I learned and researched and I lift correctly. I'm too old to be screwing up my joints and muscles with incorrect form. I work shoulders, back and biceps, chest and triceps, legs, and abs. I change up routines, I incorporate cardio (jumping jacks, jump rope, burpees, mountain climbers) all in between sets too. I'm careful about time in between sets, form, etc... it's important.
Diet... that's so so so huge. I'll just give examples of how I eat. NOTE: I definitely cheat, and I notice immediately when I do. I still do it, and I over-do it sometimes. But, hey... it's life, and I love my wine and beer, pizza, chips, and loaded fries...
Cheating is important (ONLY ON YOUR DIET!!!)
Typical day for me would be:
MEAL 1: egg white omelette (I use olive oil spray, pepper, garlic powder, onion powder but NO SALT - add broccoli, some low fat or fat free cheese, onion, peppers....whatever... but no junk)
OR three hard boiled eggs - I only eat the yolk on one.
Coffee. I have to have my coffee and I do use French vanilla cream - it's one of the few things I allow myself.
MEAL 2: fresh pineapple and fat free cottage cheese. I try to keep a lot of my dairy and fruit early in the day.
MEAL 3: baby spinach salad with grilled chicken, broccoli and cauliflower, onion, peppers, hard boiled egg and a just a small handful of unsalted sunflower seeds. With balsamic vinegar only.
MEAL 4: marinated grilled chicken breast(boneless/skinless), steamed asparagus
MEAL 5: turkey burger (no bun and made with panko instead of regular bread crumbs), steamed broccoli and cauliflower
GYM
MEAL 6: protein shake
There are so many variations, and I have tons of recipes in a drawer. Sometimes I have to have comfort food. I make a "pasta bake" that is spaghetti squash mixed with some light sauce, artichoke hearts, zucchini, ground turkey, and topped with just a little mozzarella (low fat or fat free) bake in the oven for an hour. YUM.
I buy turkey sausage now and then and grill that up with onions and peppers. YUM
I make a stuffed cabbage casserole, using no salt tomato sauce, ground turkey, cabbage, brown rice, and various seasonings. YUM
Stuffed peppers - healthy
Balsamic glazed butternut squash
veggie and egg baby quiches
cauliflower patties
etc... etc... but there are some key things. I don't drink ANYTHING but coffee (one cup a day), water (I use a lot of lemon and lime). sometimes green tea. I'm off that kick but I want to get more - real green tea too - not the sugared up shit. Gotta be VERY careful to read labels too.
I use unsweetened (30 calorie) almond milk in my protein shakes - sometimes throw a banana in, and/or peanut butter (natural peanut butter).
There are good lists of fats that are acceptable - I try to follow them. Olive oil, natural peanut butter, sunflower seeds.
After six months of doing this - pretty regularly (I cheat more now that I hit my goal weight - at first I was VERY strict - for several months) I went from 140, big belly and totally out of shape to 125, lean and muscular. I haven't weighed 125 since before Bunt was born. Almost 10 years ago - even with the infidelity diet... which - this is SO much healthier BTW.
When I cheat - I try to keep it to a minimum. I LOVE chips and dip and snacks. Now I buy hummus and whole wheat, low fat crackers. When I have my wine, I buy skinny wine, and I mix it with seltzer. Mostly seltzer with a splash of wine. If I drink beer, I keep it low cal and add lots of water in between. Moderation.
Eat out... yes, I might have a burger ON A BUN (gasp), but I will order the turkey burger. I will have fries too... but not many. I might have a grilled chicken sandwich with avocado and BACON (gasp), but on a whole wheat bun and NO MAYO.
If you want to give me some ideas of foods you love to eat - I can help you come up with some variations, or a meal plan.
OH - another thing. supplements. I try not to get too crazy with them - and here's what I take and why. Multivitamin for menopause (I'm only perimenopausal but I think I need this vitamin), I take Omega 3's. Like fish oil, but no fishy taste. I researched for that... because they are important and I hate fish. I don't even choke down albacore tuna anymore (used to in hot sauce).
I take a pre-workout, simply to really maximize my stamina and explode that workout. I like it - some people don't. BCAA's - branch chain amino acids... because they are important - but I forget why
and I keep whey protein on hand. I don't always take it, but when I do it's after my workout (within an hour) and normally when I work out late and too late to cook.
You know I have Bunt - who is CF. DS17 too. I batch cook my food a couple days a week, and still cook for them. Most people do it Sunday - I do mine Monday evening after workout... because there is NO WAY you can keep up cooking that much, with different meals for everyone. For instance, when I make my pasta bake - I also make one for the boys. With real pasta, ground beef, etc... if I throw burgers on the grill - I do mine turkey - and I mix up and make a batch of regular cheeseburgers for them too. They also eat a lot of mac and cheese, frozen crap, etc... for Bunt - it's good for him - all that salt and fat. So my situation is somewhat tricky. Chef Boy-R-Dee isn't a bad thing in my house (for him anyway). I won't touch that shit
OK I've talked enough.... see what you think about all that...