Re: The Time article.
The piece is indeed poorly written, superficial and badly supported... like many Time articles. They basically assert that because it so easy to offset calories by eating after a workout burning fat is difficult. True enough, it is easy to consume more calories after a workout than you burned during it, but just because many of us do that doesn't mean we must do that. Why not just heed this lesson and not eat? And besides, the concept of "calories" is so 1990s. :)
But however poorly supported, their assertion is correct. I'm no fan of Time Magazine. But I am someone who lost 100 lbs in 2006 and then 50 more this summer without any aerobic exercise other than normal day to day activity. That led me to investigate this issue. And my mention of Time Magazine is only because I'm glad to see someone in the press at least floating the idea even if they can't get their head and their prose around the real meat of the issue.
The real reason almost no one loses fat on a treadmill or in spin class (and I am referring to "fat", not generic "weight") are more nuanced than Time reports and more long winded than I am willing to go into here - altho I have plenty of wind, despite my lack of exercise :)
To give you some pieces of it (and you will find these things to be easily verifiable):
Your body won't burn fat when it is making insulin. And eating carbs before, during or after a workout in almost any amount can produce an insulin response and does in most of us because we are so used to eating excessive carbs. It's a generalization, but for most of us a bottle of Gatorade during a workout will be enough to trigger insulin. Eating anything with carbs equal to a bagel before working out will probably do it. Insulin is called the fat storage hormone. It takes sugar from your blood and stores it as fat. It is worth repeating... if you eat, you probably produce insulin, and insulin creates fat. When insulin is at work, fat is being stored, not burned. Period. Calories in and calories burned are insignificant in that environment. If you want to lose weight, quit your gym, sell your shoes.... and have your doctor talk to you about blood sugar and insulin.
Additionally, your body when exercising will burn all the available glucose (sugar/carbs) in your body for energy, then burn the glycogen stored in your muscles, and only then start thinking about burning fat (and muscle). Which is why they say you have to work out for at least 30 minutes to get results (a one shoe fits all generalization, but almost all nutritional discussions are). Problem is aerobic exercise is considered an emergency situation by the body - and in fact it is - so the body begins trying to preserve fat. About the time your body starts looking for something else to burn, hopefully fat rather than muscle, it also slides into panic mode and starts hoarding.
Ever been to a marathon and seen people with pot bellies or big asses running? How can that be when they run dozens of miles a week to train? It's probably for two reasons. One, they "carb up" to work out, and carbs become glucose and lead to insulin. And two, their bodies are afraid these grueling workouts represent the way it has to live from now on and works hard to maintain status quo. I have a triathlete friend who runs an ungodly number of miles per week and can't beat those last 15 lbs she has been trying to lose for 4 years. It's likely because she eats a carb based diet and exercises too much. Her grueling exercise schedule probably keeps her from gaining additional weight. There is no doubt she can eat more (and does) because she burns more. But all that burning does nothing to get those last few lbs off and may be the reason it sticks to her. This is difficult for her to accept because exercise is a religion for her. Her trainer supported what I am saying, so she quit seeing him.
I'm not saying aerobic exercise burns no fat, ever. I am saying it only does so in the briefest of windows and then only if your diet already has you burning fat by default (we humans are either fat burners or sugar burners and diet determines that).
You know it's true in your heart. One thing the Time article did get right is pointing out that America's obesity and diabetes rates have exploded during the same decades that the number of gyms, trainers, diet books and media discussions of weight also multiplied. I live in a Texas city, and when I was in college there were three gyms in town. Now there are 3 on my street and 2 more within a 10 minute drive. Half the people I know have trainers, heart monitors, gym memberships and a Nintendo Wii Fit and still they move up a shirt size every couple of years. You've seen the same thing, and the numbers are readily available. America is obsessed with exercise. America is also getting fatter and fatter. Do the math.
Now, let's take a breath.... I am not anti-exercise. I said this before: Exercise helps regulate insulin and that could and should indirectly lead to fat loss in most people. It also is fun, makes you stronger, tones your body, and improves your heart, lungs. And moderate, non stressful exercise is extremely important for the brain. People who don't move can even develop severe cognitive problems. And people who are sedentary are likely to gain weight. Daily walking is a great habit. Your brain will thank you.
But for those of you who swear you have lost fat (not muscle, not water, but fat) on aerobic exercise, I will still insist it is because a) you helped balance your insulin response and b) exercising, for many, makes them more mindful of diet. Unfortunately, exercising also makes many of us LESS mindful of diet, and hungrier, exactly the assertion of the Time article.
If you lost actual fat during periods of aerobic workout, it is certainly from these 2 factors (insulin and diet awareness) and not from hours spent running or biking. It's also likely you exercised in moderation. Excessive exercisers damage their bodies in a number of ways. I think humans should be daily walkers, not runners, bikers or spinners. At least not if their intention is to burn fat.
Ultimately, what I am saying is that the idea of aerobic exercise as we know it does not merit being discussed as an equal partner to diet. It's not 100% inconsequential, and it appeals for other reasons but it is so inconsequential to fat burn that an aerobics class membership is a waste of money and ever increasing levels of exercise are a waste of time (and in some cases a detriment to your health) unless you have other goals. And the idea to lose weight we need to log countless hours of exercise is indeed, as Time says, a "myth". And it's misleading to overweight people who are already frustrated. The last thing they need is to feel shame about not exercising enough in addition to the shame we all feel being overweight.
100 years ago no one would have suggested long periods of aerobic exercise for fat people, and 10 years from now we will all be conceding it was overstated. By then, any one with an education in exercise and nutrition will be acknowledging that the fitness industry pushed it well past the point where it was scientifically justifiable, while food companies urged us to work out more and keep carbing up.
Indeed, the whole calories in calories out paradigm is shifting - which is why you see so many diets that claim you can eat as much as you want of certain foods. Now that we understand hormones better (Leptin was only discovered in the 90s, and insulin research has multiplied now that Diabetes is becoming an epidemic), calories and the burning of calories are coming to be seen as practically irrelevant. Hormones like Insulin and Leptin are the real story. That's just newer information and harder to explain information. And don't expect personal trainers or web sites devoted to exercise to be the first to tell you about it.
Ask your doctor. I did. While I was losing 150 lbs in 3 years without exercise.
- 8/13/2009 1:04:21 PM