Placeholder Image

字幕列表 影片播放

  • "The ExerciseMythfor Weight Loss"

  • When trying to lose weight, which is more important:

  • diet or exercise?

  • A national survey found that a "vast majority" of Americans

  • trying to control their weight

  • believed that food and beverage consumption

  • and physical activity were equally important.

  • Seven out of ten went with equally important,

  • about two out of ten thought exercise was more important,

  • and only about one out of ten chose diet.

  • The vast majority of Americans are wrong.

  • It's easy to understand how people might think

  • diet and exercise play equal roles.

  • After all, our weight is determined

  • by the balance of calories in and calories out.

  • What people may not understand

  • about this energy balance equation

  • is we have much more power over the "calories in" side.

  • In fact, on a day-to-day basis we have full control,

  • we could choose to eat zero calories

  • or 10,000 calories.

  • But most of the "calories out"

  • tend to be outside of our control.

  • Unlike wild animals who tend to burn

  • most of their calories on activity,

  • about 60 percent of our daily calories

  • are used up just to keep us alive,

  • what's called our resting, or basal, metabolic rate,

  • thanks in part to our energy-intensive brains.

  • Even if you stayed in bed all day,

  • you'd still burn more than 1,000 calories

  • just to fuel the basics like thinking, breathing,

  • keeping your heart pumping.

  • In contrast, even most "active" people

  • accrue less than two hours of exercise a week,

  • which may average out to be less than 100 calories

  • burned off each day.

  • That's only about 5 percent

  • of the total daily energy expenditure,

  • the "calories out" side of the equation.

  • So, the 2,000 calories we may take in every day from our diet

  • can exert 20 times more influence than exercise

  • over our weight destiny.

  • Most people believe that exercise is "very effective"

  • as a way to lose weight,

  • but this has been referred to as a myth

  • in the scientific literature.

  • In fact, it's been labeled

  • one of the most common misconceptions

  • in the field of obesity.

  • Yet virtually all formal weight-loss guidelines

  • include some sort of physical activity recommendation.

  • Can you outrun a bad diet?

  • Let's see what the science says.

  • Population studies have certainly found

  • strong correlations between physical inactivity and obesity.

  • But does a sedentary lifestyle lead to obesity,

  • or does obesity lead to a sedentary lifestyle?

  • It probably works a little bit in both directions.

  • To prove cause and effect,

  • and also quantify the relationship,

  • you really have to put it to the test.

  • Dozens of randomized controlled trials

  • involving thousands of participants

  • have been published on the effects of exercise

  • on weight loss.

  • Physical activity was not found to be an effective strategy.

  • For example, if you look at the studies

  • that tried using exercise alone to induce weight loss,

  • over an average of about five months,

  • people only lost about three pounds.

  • When you put all the studies together,

  • it looks like it took around six weeks of exercising

  • to get people to lose a single pound.

  • That was exercise alone, though.

  • What about as an adjunct to diet?

  • If you randomize people

  • into a diet and exercise intervention

  • versus just the diet alone,

  • the added exercise group does do better,

  • but the difference in weight loss

  • only averaged about two pounds.

  • The studies lasted between 3 and 12 months,

  • and all of that extra prescribed exercise

  • only seemed to translate into a few pounds.

  • The two-pound difference was statistically significant,

  • which means we're pretty sure it was a real effect,

  • but losing two pounds over a year's time

  • can hardly be considered clinically significant.

  • As a general rule, researchers like to see

  • at least a five- or six-pound drop.

  • In a meta-analysis of 18 randomized controlled trials

  • lasting a minimum of six months,

  • the diet-plus-exercise group

  • failed to significantly beat out the diet-only group at all.

  • There appeared to be no long-term benefit

  • to encouraging people to add exercise

  • to their weight-loss regimen.

  • What is going on?

  • Maybe exercise is just better

  • at preventing people from regaining weight.

  • No.

  • The vast majority of randomized controlled trials

  • examining weight-loss maintenance

  • also failed to show an exercise benefit.

  • Part of the problem is compliance.

  • It's one thing to tell people

  • to adhere to an exercise regimen;

  • it's another thing for them to actually do it.

  • When the same randomized controlled trials

  • were re-analyzed to exclude people

  • who flouted the instructions,

  • and analysis was limited to just those

  • who actually put in the time and sweat,

  • a clear advantage to exercise emerges.

  • Exercise only works if you actually do it,

  • though one reason people may become rapidly disillusioned

  • with their new gym membership

  • is their gross overestimation

  • of the capacity of exercise to burn off extra calories.

  • A slice of pizza has about 300 calories.

  • That converts into an hour of brisk walking per slice,

  • an hour a slice!

  • How many kids are jogging two hours a day

  • to burn off their happy meals?

  • Who's got time to climb 50 flights of stairs

  • to take care of the calories in just one Oreo cookie?

  • That's one of the reasons

  • that what we put in our mouths is most important.

  • Public health researchers have been experimenting

  • with including labeling on junk food.

  • Which label is more informative?

  • This one or these?

  • Still want that Toblerone if it means you have to walk

  • two hours?

  • Or cookies you'd have to skip rope

  • for 81 minutes for?

  • I think I'd run an hour just to avoid having to eat

  • shrimp-flavored potato chips.

  • Labeling fast food menus with little pictograms

  • of exercising stick figures was found to help nudge people

  • towards lower calorie options.

  • Seeing that the decision to supersize your fries

  • would mean walking an extra three miles that day

  • or that choosing the chicken salad

  • over the garden salad could mean having to run

  • nearly three miles,

  • people are more likely to make the healthier choice.

"The ExerciseMythfor Weight Loss"

字幕與單字

單字即點即查 點擊單字可以查詢單字解釋

B1 中級 美國腔

The Exercise “Myth” for Weight Loss

  • 14 2
    VoiceTube staff 發佈於 2024 年 03 月 26 日
影片單字