The Truth About Exercise and Weightloss
There is a false belief, perpetuated by beverage companies and certain TV shows, that the key to weight loss is exercise. While exercise is important for health, and will certainly aid in weight management, the food you eat is far more impactful when it comes to losing weight.
To put things in context. you'll need to run a full marathon (26 miles) - without putting a thing in your mouth - just to lose a single pound pound of body weight.
Food is far more important for weight loss than exercise is.
On average, people today are working out at the same level that they did 30 years ago. However, obesity has skyrocketed.
What has changed?
Easy. People are consuming more calories than ever before.
Conclusion: extra calories from food are to blame for weight gain, not lack of exercise. Yep, the junk food companies are lying when they claim we are a lazy generation.
People often miscalculate how calories from food excesses add up to a much bigger number than the calories burned working out. Most people will exercise just once a day. But the opportunity to make a poor nutritional choice presents itself 10-20 times a day, at least. That's because unhealthy food is available ubiquitously. Your kitchen, the office, the gas station, the book store. Heck, even your gym!
To burn off a burger (500 calories), you will need to do 45 minutes of cardio workout. A single slice of pizza has about 300 calories, the equivalent of 20 minutes of running at a 9 minute-a-mile. A tall caramel macchiato from Starbucks has 180 calories; you'll have to walk 2 miles to burn them off. To work off a pint of beer (250 calories), you'll need to do 30 minutes of weightlifting. Should we continue with some candy and potato chip examples, or do you get the drift?
Another overlooked aspect of exercise is compensatory calories. On days we work out, we tend to eat more because we "earned it". This psychological phenomena happens to almost everyone. Who hasn't completed a workout, only to drink a congratulatory smoothie with more calories than burnt?
Lastly, another important point to consider. Besides weight gain, a poor diet is much more harmful tou your health than the effects of physical inactivity, alcohol and smoking - combined. So even if you aren't overweight, a nutrient poor diet can lead to adverse health effects such as hypertension and non-alcoholic fatty liver disease. This can happen even if you are exercising regularly.
The more you exercise, the less you burn.
Your total daily energy expenditure is comprised of resting energy burn plus whatever you burn as a result of physical activity. The more you workout, the more you burn - a 30-minute run will burn 250 calories; do it for an hour, and you'll burn double.
However, your resting energy burn is also affected by exercise. Scientists measured the resting energy burn of over 300 volunteers from all over the world. They were surprised to discover that once physical activity increases above a moderate level, the body adapts and reduced its metabolism in order to conserve energy (the graph on the right side of the chart).
Exercise is very important. For health.
There are so many reasons to exercise:
Regular workouts can help reduce the risk of disease, including type 2 diabetes, cardiovascular disease, dementia and some cancers.
Exercise releases endorphins, chemicals that make you feel good, naturally.
Working out helps reduce stress, which is a factor that leads some people to eat unhealthy comfort food.
On days we exercise, our sleep improves. Better sleep means less hangry episodes then next day.
Exercise may also boost the immune system.
Athletic ability that comes with regular exercise can also boost your self confidence.
When you exercise, your body slowly replaces fat with muscle. You may not see numbers dropping on the scale, but your dimensions may decrease, as muscle is more dense than fat. Dropping a jeans size, while flat lining on the scale is definitely a thing.
So, yes, by all means, exercise. As much as you possibly can, while still enjoying it and staying injury free.
Bottom line: Weight loss is 80% Nutrition, 20% Exercise.
Even if you don't exercise at all, by counting calories and eating mostly healthy, whole foods, you will shed pounds. Lots of them!
On the other hand, working out regularly, but with no regard to what you eat, will not lead to weight loss.
What has your experience been?
1. Noakes et al - It is time to bust the myth of physical inactivity and obesity: you cannot outrun a bad diet - British Journal of Sports Medicine, April 2015
2. Pontzer et al - Constrained Total Energy Expenditure and Metabolic Adaptation to Physical Activity in Adult Humans - Current Biology, 2016