Body burns fat depending on how much Oxygen is in the blood stream. Basically lower the heart rate, more fat is burned, higher the heart rate the more Glycogen is burned, because Fat needs Oxygen to burn.
Also its not as simple as taking in and taking out. Metabolic rates have a huge key to play. Its also why its hard to tell actually how many calories we burn in a day. I personally have a very good Vo2 and heart rate. My standing heart rate is very low, it can get into the low to mid 60's. Yet i am about 21%-23% body fat. It takes forever for my heart rate to get going when i run. i could do 5 all out sprints for a minute each and still not struggle to catch my breath. Someone could be the same weight and couldn't be in shape as i am. So, it hard to go through general rules of thumb on this. I am very healthy, but not by looks. So the numbers can lie there are a lot of things going on. That's why going by what machines say you burn is tough to go by.
Low carb diets are totally unnecessary. Carbohydrates can really help in maintenance of muscle in the long term and have no effect on fat loss when calories are kept the same.
High protein is always a good idea, but low carb - why why why. Next you'll be telling me I'll get fat if I eat carbs after 6pm
I agree if your exercising a lot carbs have been shown to help in repairing the muscles. But its not as much as you think, maybe about 10-20 grams of carbs after you exercise is all you need. The best source would be maybe a protein shake made from fresh fruits.
But not everything is as simple as calories. What you eat MATTERS!!! If you have read any of the books coming out about Carbs, its not that simple. Especially if you think all carbs are the same, there not. They are the same in energy expenditure, yes they are, but on other functions in the body, no there not. Especially when talking about sugar.
Sugar, when it enter's your body, it forces your body to produce insulin, to maintain a blood sugar balance. This is known, but it puts the body into over drive (sugar high/crash). If you keep doing this over time, you will develop a resistance to sugar, meaning you wont get the high/low as before. I have experienced this being a pop drinking for 20+ years then stopping then having a can of pop again. I was totally wired and then crashed. But 5 years ago one pop wouldn't effect me like that. Its because i was insulin resistant, meaning that my body overproduced insulin. This has a nasty side effect, insulin regulates how much fat is being stored in our body. More insulin, means more fat will be stored, beyond energy expenditure. Also a nasty side effect with sugar is that it release pleasure hormones from the brain and will cause us to crave it. Anyone who has tried to kick sugar, will get this, you start thinking about a candy bar or pop, your brain will tell you, that is some good stuff, and you have to really try not to eat it. This creates a nasty cycle that has lead to a rise is obesity and type 2 diabetes, as well as other host of diseases and health problems.
So if i had to rank carbs, i would eat veggies first, then sweet potato, then potato, then brown rice, then rice, then pasta, then bread, NO SUGAR
Believe me, i tried it all. I've done the crash diet for 6 months, 500 calories a day. I lost 40 lbs, then i was stuck there for 2 years. I was eating 50% carbs, and split on fat and protein. I ran 3 times a week and lifted weights the other two days. I was eating less than what i was working out, DID NOT LOOSE WEIGHT. Then i stopped drinking pop, and i started going low carb, and i dropped 30 lbs to were i am at now, 200 lbs. My diet is about 15% carbs, 40% fat, and 55% protein, roughly. I feel great, i am not bloated anymore, i just kept loosing weight. Guess what, i am eating the same calorie expenditure as i was when i was stuck at 230.
So let me ask you, explain that please?