[Question] BMI, Dieting, and Exercise

Smith332
Smith332 Posts: 7
in Health and Weight Loss
I'm absolutely new to this terminology, I understand though that BMI stands for Basal Metabolic Intake.

I understand that my BMI is what is needed to maintain the function within my body, but since Muscle is the first thing to be consumed when you haven't met up with those demands from your BMI (not your fat first), what is the point of increasing your BMI through cardiovascular exercise when your on a weight loss plan?

If that question didn't make any sense, I'll attempt to make it plain. It's basically saying that if you starve yourself, your body will consume your muscle mass first for the needed calories and than take on your fat mass whenever you need calories. But since cardiovascular exercise increases your BMI, wouldn't you be doing more damage to your body than good by allowing this variable to increase? Since this is what is driving the need for your calorie intake, you would be eating more mass away from your muscles than your fat.

Another fair question I think: Is your BMI the primary driver of your calorie intake?

Replies

  • RoanneRed
    RoanneRed Posts: 429 Member
    This won't address everything in your question, but:

    - Watch out for confusion between BMI - Body Mass Index and BMR - Base Metabolic Rate

    - Selection of which body tissues to consume in a calorie deficit is more related to missing nutrients than simply the number of calories. If your body only requires calories, it should consume fat stores as there is more energy (calories) in a gram of fat than in a gram of protein (from muscle). If your activity has triggered your body to build cells (eg. muscle in your legs) but you haven't eaten enough protein to provide the building blocks for cells, the your body may need to break down muscle from another part of your body that it may not think you need as much.
  • Smith332
    Smith332 Posts: 7
    Ah, I see it was "Index" instead of "Intake", doh! I was looking at my BMR and was thinking that BMI is the technical term.

    - Selection of which body tissues to consume in a calorie deficit is more related to missing nutrients than simply the number of calories. If your body only requires calories, it should consume fat stores as there is more energy (calories) in a gram of fat than in a gram of protein (from muscle). If your activity has triggered your body to build cells (eg. muscle in your legs) but you haven't eaten enough protein to provide the building blocks for cells, the your body may need to break down muscle from another part of your body that it may not think you need as much.

    So your saying that whenever your building cells (via exercise), protein is the main building block for those kinds of cells? Also those additional muscles would demand more calories from you as they contain the energy that muscles would need to perform work?
  • RoanneRed
    RoanneRed Posts: 429 Member
    I believe protein is broken down into amino acids that are then used to build new cells (of all sorts, not just muscle).

    Although having more/stronger muscles does require more energy even when doing nothing, the difference is minimal throughout the day so shouldn't be relied upon to allow you to eat extra.

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