Ask an expert
Question

07 Jun 2004

Fat Burning Theories<br>
Hi Conrad

Please clarify this issue that drives me mad!
Some experts say that to burn fat you must exercise at low intensity for an hour at approx 65% - higher than 65% & you burn carbs or glycogen.Other experts say train high intensity 80% & you'll burn fat? (eg Body forLife)

My theory: Both exercises will make you burn calories (if you reduce intake of calories & exercise you will burn fat) & if you do not have carbs in your system your body will burn fat. No carbs & no fat, your body burns muscle.

High intensity will boost your metabolism for 48 hrs thereby burning more calories overall - low intensity does not have this effect. So which is best?

Please provide your side. Also, how does the intensity level of exercise make your body burn different sources of energy?

Thanks
Answer 455 views
Expert
Bodybuilding
body building

01 Jan 0001

CBC,

Traditonal views are held that at about 60 to 65% of your VO2 Max you'll burn fat and that it must be done for an extended period. That is correct because at that intensity you'll be in the fat burning "zone."

At a higher intensity you'll be burning carbs. But, have you ever considered that once you have burned your carbs you'll switch over to fat as the remaining energy source?

Your theory is correct-that is why I am a big supporter of limited carb intake when trying to lose fat or to cut. Of course I would not advocate limiting carbs too extensively when doing weight training but definitely when doing cardio.

The increased metabolism is a benefit for a few hours after training, especially at a high intensity but I'm not aware that the effect lasts for 48 hours.

I'm a big proponent of the Body-for-Life way of doing cardio. Either that or training at a medium to high intensity for 15 to 20 minutes. When combined with limited carbs you should see results. Just still remember to eat properly, when you do consume foods and carbs though. No sweets or simple, high Glycemic Index carbs.

The carbs you should be aiming for are Low GI such as beans, barley and anything with a GI of 50 or lower.

Keep well,

Conrad Booysen-Biokineticist
The information provided does not constitute a diagnosis of your condition. You should consult a medical practitioner or other appropriate health care professional for a physical examination, diagnosis and formal advice. Health24 and the expert accept no responsibility or liability for any damage or personal harm you may suffer resulting from making use of this content.
Voting Booth
Have you entered our Health of the Nation survey?
Please select an option Oops! Something went wrong, please try again later.
Results
Yes
32% - 9467 votes
No
68% - 20213 votes
Vote