Exercise vs. Diet

Recently I was asked to do an article on how food affects your metabolism. I spent hours searching for and reading scientific journals and found out a few things which may make your quest for better health more productive. I hope that this saves all of you a lot of time and provides some direction as to where your efforts should be going.

There is a certain amount of energy required to keep you warm and keep the organs like your heart, liver, and brain up and running. I know some of us have that crazy second cousin who we wonder if their brains are working but the same applies to them as well. This is referred to as basal metabolism. Basal metabolism is regulated by your nervous system.

There are a few studies which show that a calorie restricted diet leads to a down shifting in the nervous system namely the sympathetic nervous system which regulates heart rate and blood pressure. This is the reasons that after a certain amount of dieting people just start spinning their wheels. Well, no worries there is something that you can do to keep the progress going. Exercise has been shown to increase nervous system activity and metabolism. Activity has been shown to represent up to 50 percent of the calories used by active people in comparison to the 15 percent of calories used by sedentary people. The caveat to keep in mind is that working off a 273 calorie Snickers bar takes a lot more work and time than just avoiding eating it in the first place.

Unfortunately, the magic of exercise is somewhat short lived. The increase in metabolism lasts about 48 hours and this depends greatly on the mode of exercise. This means that consistency is the key here. Some exercise such as slow paced aerobic workouts do not have the 2 day period of increased metabolism, it is much shorter. The longest period of increased metabolism were noted in individuals after weight lifting and other anaerobic workouts. I know for some of you this will bring to mind the question; well doesn’t aerobic exercise burn more fat? The short answer is no. This is a misconception that I will address in the near future, so stick around.

I would like to leave you with this. If your dieting stalls and you are still interested in losing weight, cutting more calories may not be the appropriate action. Including more activity into your day is a sure fire way to increase your calorie deficit and keep that metabolism burning like a furnace to help you lose that unwanted fat. Diet and exercise should be used together for the most effective weight loss program; one without the other is half an effort, which usually leads to frustration and disappointment. Best of luck to you in your efforts to live a healthier and happier lifestyle. Keep the questions coming and I will keep the articles coming!

References:

Effect of chronic food restriction on energy balance, thermogenic capacity, and brown-adipose-tissue activity in the rat, Nancy J. Rockwell and Michael J. Stock

Reflex control of the circulation during exercise: chemoreflexes and mechanoreflexes,

L. B. Rowell and D. S. O'Leary

Physical activity – a neat solution to an impending crisis

Alison M. McManus
Institute of Human Performance, University of Hong Kong, Hong Kong

A Single Bout of Concentric Resistance Exercise Increases Basal Metabolic Rate 48 Hours After Exercise in Healthy 59–77-year-old Men, David L. Williamson and John P. Kirwan