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Fine Tune Your Fat Burning

Monday, March 17, 2008

I normally try to focus here on ideas related to motivation and the mental aspects of fitness and weight management, but this entry is going to talk about some info you can use to make sure you're getting the most out of your fat burning potential.

We all know that getting fit and healthy is more about losing fat than about making the number on the scale go down. In fact, most of the things people do to get dramatic or fast results on the scale either don't have much to do with losing fat, or may actually make it harder by forcing their bodies to cannabalize muscle and organ tissue--the same tissues that actually use the most fat as fuel.

So, if you want to be in the business of burning fat, it pays to know as much as you can about how and when your body actually does that.

Fat is your body's "default" energy source. It's the preferred fuel source when nothing special is going on, while you're at rest or doing fairly light activity. You're never burning just fat, because your body can't burn fat unless some glucose (sugar) is available, along with oxygen. At very low intensity levels (like while you’re sitting in front of your computer reading this) you’re body might be getting 80% or even more of the energy it’s using from the fat you have stored in your body.

The problem, from a weight loss perspective, is that you’re not burning up very much total energy (calories) when you're at rest, so 80% of this small number of calories doesn’t amount to much actual fat burning. At the other extreme (like when you’re running a 100 yard dash) you’re burning tons of calories per minute, but virtually no fat, just carbs (glucose). That high intensity level is great for creating a calorie deficit, but by itself, it may not be the best way to maximize fat loss, mainly because you can't maintain that level of intensity for very long.

Somewhere in between these two extremes there will be an ideal mix of activites and intensity levels that produces just the right combination of total calories burned and total fat burned. Finding your ideal mix is the name of the game when it comes to losing fat. And this is not the same thing as trying to create the largest calorie deficit you possibly can. If you think about it for a minute, you can see that there's a limit on how much fat your body can use in a day, because this is determined mainly by the intensity of your activity. If your calorie deficit is larger than the amount of fat you can burn, you are going to lose some muscle and organ tissue.

Fat Burning Facts You Need to Know

Your Aerobic Threshold and your heart rate. There is an actual “point of maximum fat burning” at which your exercise intensity and your body’s ability to use fat as fuel combine to generate the largest amount of fat burned per minute of time spent. That point is called your aerobic threshold. This point differs for each individual based on several factors, including your fitness level and how efficient you are at doing that activity.

Your exact aerobic threshold can be determined by a procedure that measures and analyzes your exhaled breath while you exercise at different intensity levels. You can probably get this done for around $150-200 at a college with a graduate level exercise science program, or at many athletic training programs or sports medicine clinics. It will also tell you what heart rate corresponds to your maximum fat burning point.

Fortunately, though, you don’t have to know exactly what your personal aerobic threshold is in order to use this approach effectively for weight loss. The amount of total fat burned shifts gradually upward until you get to your aerobic threshold, at which point it starts declining fairly rapidly until you get to your anaerobic threshold--the point at which your heart and lungs can no longer deliver enough oxygen to burn fat, and lactic acid starts builing up faster than it can be removed, causing your muscles to "burn" and eventually, forcing you to stop or slow down your activity.

For most people who are neither very unfit nor extremely fit, you’ll be working close to your aerobic threshold, and burning the most fat, when your heart rate is between 65-75% of your estimated maximum heart rate.

Now, I hope you’re not sitting there thinking something like: “Oh, good, now I can drop those awful high intensity interval training workouts, and focus on the easy stuff.” The idea here is not to downgrade all your high intensity workouts into lower intensity workouts. You do not want to decrease your total calorie burning, or miss out on the health and fitness benefits of including some high intensity exercise in your weekly schedule. The goal here is to simply expand your focus so that you’re thinking about burning fat as much as you are about burning calories. Your ideal plan will still include a mix of high and low intensity exercise, strength training, and as much other activity as you can manage to include in your life.

You’ll need to figure out for yourself what kinds of activities keep your heart rate in the “aerobic threshold zone” of 65-75% of your maximum heart rate. If you haven’t done it already, this might be a good time to think about getting a heart rate monitor, or really familiarizing yourself with the Rating of Perceived Exertion scale. For many people, though, it will probably be as simple as adding a little uphill to the daily walk or bike ride.

Timing your meals to maximize fat burning. Another thing you can do to enhance your fat burning potential during your moderate exercise sessions is to avoid eating anything (and especially fast-digesting carbs) for an hour or two before your workout. Eating carbohydrates stimulates your body to release insulin into your bloodstream, which enables your body to get glucose into your cells where it is used as fuel. Insulin also inhibits use of body fat as fuel a little, which is fine when you’re working at high intensity levels that don’t burn much fat anyway—your body will do the fat burning when it’s making up for your calorie deficit after the exercise. But you won’t need as much glucose for a lower intensity workout, and minimizing the insulin response right before exercise will allow your body to take a little more fat out of storage and get it to your active muscles. If you can handle the amount of aerobic threshold exercise you have planned without a pre-workout meal, do that. If you need something to eat to provide energy or keep your blood sugar levels from dropping too much, try eating a snack that includes protein and complex carbs an hour or so before your workout. But don't risk getting dizzy or having a blood sugar crash just for the sake of burning a few more fat calories.

If you're one of those lucky people who have time for lots of physical activity in your day, a great way to maximize fat burning and fitness is to include both a fairly short, high intensity workout and a longer, aerobic threshold workout.

A final thing that's important to keep in mind is that all activity helps burn fat. Many studies have shown that the difference between people who find it easy to maintain their weight and those who tend to gain easily is often not in how much they eat--it's at least partially in how active they are even when "at rest." Your hollow legged friends may seem that way mainly because they do a lot of fidgeting and moving around even when they're sitting in front of the TV.

So, don't just sit there. Fidget.

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Member Comments About This Blog Post
    I am glad to hear that fidgeting is good! It never has occurred to me that it could be a good thing. We are bombarded with the media telling us we need to buy a machine, join a club or some other method of defined exercise in order to be healthy - when just getting off of the sofa and moving is good beginning -- even swinging our legs while on the sofa is a start, right?
    Your article is very informative and inspiring. Thanks! emoticon
    3145 days ago
    This article was very helpful. I do have one question. If your below the 65-75% are you still burning fat?
    3238 days ago
    In Nashville, TN, there is a contest going on that is kind of like the biggest loser, but is all about inside health. We are competing on two teams of women who have been measured on the inside...not weight...and are working out every morning at D1 Sports Training Facility. We really could use some help with our caloric intake and output, as some of the women are working so hard that their bodies are eating their lean mass instead of fat. We are all needing menus to match our caloric needs with our output. Can you give us some ideas fto go for menus that would prepare really, really healthy eating, that would also tell us our calories? Check us out at OnTheHomeStretch.com
    3242 days ago

    Comment edited on: 4/6/2008 10:46:52 AM
    When my allergies keep me from working out for just a few days, my scales show a huge increase in my body fat. Are scales an accurate way of measuring body fat? How can a 2 or 3 lb increase make such a whopping difference?
    3245 days ago
    i learned that we have to not just lose weight to burn fat; but, we need intensive exercise activities to do the job
    3249 days ago
    How do I find out what my Aerobic Threshold is?
    3252 days ago
    Coach you're right on target. I noticed when I first started exercising that if it wasn't focused on the "threshold" I wasn't really achieving any loss in weight. Once I talked to the folks at the University Gym, and got my heart rate monitor I noticed marked improvement of the amount of weight I was loosing. Now I'm faced with maintaining and knocking off a few holiday pounds now and then. I work at my heart rate of 145 ~ 155 for me and I do just fine.
    3254 days ago
    This is really helpful! I had my 2nd measure of body fat % at Curves today, and the number came down, but not into the "good" range yet. This helps me understand what I can do to change that number.

    Is it true that the BIA method of calculating body fat is also influenced by whether you have recently drunk water or recently exercised?

    3254 days ago
    A portable phone is a wonderful exercise tool. I remember the Bad Old Days sitting on hold with bad music playing in my ear I would pace back and forth as far as the cord would allow. Now I can get some speed up and some distance in - music is still bad, but I can walk off the frustration of "Please hold for the next available agent"!

    3259 days ago
    HI, L

    It's good to eat right after a high intensity exercise session, because that's when your body is primed to use the carbohydrates you eat to replace the glycogen you used up with your exercise, and to use the protein to repair and rebuild muscle. So, make sure that meal/snack includes some complete protein (about 20-25% of the total calories). If your post exercise meal is a snack (rather than a full meal), you would ideally want to eat enough calories to replace about half of the calories you burned with your exercise.

    Your body will use bodyfat to make up for the calorie deficit the exercise helps you create when you're at rest and operating at very low intensity levels.

    Hope this helps.
    3259 days ago

    Comment edited on: 3/20/2008 11:11:54 AM
    thanks for the great info, coach dean! i love how you are able to clearly communicate the info and your story... 1 real quick question:

    you said, "... when you’re working at high intensity levels that don’t burn much fat anyway—your body will do the fat burning when it’s making up for your calorie deficit after the exercise."

    so does this mean high intensity level workouts can be useful in fat-burning as long as we don't eat after workout?
    3259 days ago
  • STAR1970
    Great info. Thanks
    3260 days ago
  • NOMI_822
    Thank you Coach Dean, this is why I subscribe to your blog. You take valuable info that we need and write it out in a simple to understand text. I really need this as I haven't lost much since I have been on SP. I have made great strides in my positive attitude and in reducing my stress levels. I am now ready to lose the rest of my weight and enjoy this summer. Thanks Again Coach Dean.
    3261 days ago
    Thank you for enlightening me. Great information!!
    3261 days ago
    3261 days ago
    Thanks for sharing all your great information.
    3261 days ago
    Thanks, enjoy all your blogs and information

    3261 days ago
  • FIT_4_ME_4_LIFE
    Good stuff here!!
    3261 days ago
    timing of meals and work outs is sorta tricky for me. I try to go to the gym about 45 mins after I get home from work and if I dont eat I get the shakes and feel weak..Guess I will try to eat a protein drink before leaving work (around 3 if I have a 5:30 class)

    thanks for your help :)
    3261 days ago
    Thank you, I sure appreciate this great article. Lots of new ideas here!
    3261 days ago
    thank you for this informative blog. This may very well be why I haven't lost much weight after running 20 miles a week , half of them at a high intensity. I have always eaten a banana or apple an hour before my workout which is at the end of my workday. Tow things I will change and see what happens.
    3261 days ago
    Tkanks for great information on fat burning
    3261 days ago

    Comment edited on: 3/17/2008 8:28:51 PM
    Once again Coach Dean hits it on the head. Timely, well written pieces that address questions we all have - or should have! Thanks!
    3261 days ago
    okay, I am rotating my ankles as I read this. Thanks for the info!
    3261 days ago
  • BARBP60
    Very informative. Thanks
    3261 days ago
    Very interesting. Thanks for sharing!
    3262 days ago
    Very interesting, will take to heart.
    3262 days ago
    Incredible article- thank you so much! "I can see clearly now!"
    3262 days ago
    Move it ! Move it! Move it! Let's start some fat burning. Very informative.
    3262 days ago
    So there IS some benefit to my workouts first thing in the morning before I've had anything to eat! I've always suspected that to be the case...

    As usual, terrific knowledge from you Coach Dean! I really appreciate it!

    Don, Co-Leader of All Health Professionals SparkTeam
    3262 days ago
    AWESOME explanation. Thank you!
    3262 days ago
    Thanks for the tips on when to eat! I've been eating lunch and then exercising about an hour afterwards. Maybe switching my meal time forward a bit might help.

    I bought my heart monitor last week! That was a big awakening for me! I realized that I wasn't working out hard enough when walking on my treadmill.
    3262 days ago
    GREAT article - thank you!!!
    3262 days ago
  • PAMELA984
    Hmmm - lots to think about.
    3262 days ago
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