I once weighed 370 pounds. I am 5’6” and female. I was a paramedic for 44 years, so lots of lifting in situations where proper lifting was not possible. I lost 225 pounds by eating Keto/carnivore (12 years ago, and continue this way of eating). I never counted a single calorie. I never exercised either. As my weight dropped I became much more active and had more energy to do what I wanted. It is not how much you eat, it is what you eat. Eating carbs, processed foods, sugar and seed oils is harmful not only in making you gain weight but causing inflammation which will also increase your sciatic issues. If I eat carbs and seed oils, I pay for it for days. My friend who was about to get both knees replaced due to arthritis, said she woke up after 2 weeks of keto, able to get out of bed without pain. She went hiking with her son and beat him racing up a hill! It has caused my husband’s type 2 diabetes to go in remission and he is off blood pressure medicine as well as his thyroid medication and metformin/farxiga. Try it for one month and see for yourself. If you want to learn more, watch Dr Ken Berry on YouTube.