Why the 80% diet 20% exercise rule?

Leyshinka

Please help me understand why this is the general assumption to weight loss. I'll try to keep my thoughts simple using the example below:

A female athlete eats 2500 calories and burns 500 calories with exercise to maintain weight X. She stops her training and leads a sedentary life whilst still eating 2500 calories. Over time she gains weight until she reaches weight XY. She maintains this weight for a number of years. If she starts her athletic training again, burning 500 calories whilst still eating 2500 calories, my simple brain tells me that she would loose weight until she reaches weight X.

Is that not weightloss due 100% exercise?

psuLemon

Weight loss is 100% diet.. Exercise is fitness. But you can create a deficit with diet.

lambchoplewis1

lose wight in the kitchen, get fit in the gym

SergeantSausage

It doesn't matter. The only thing that matters is creating a calorie deficit.

For most folks, though, a 500 calorie defect in the kitchen is far, far easier that a 500 calorie deficit in the gym. You can cut out soda for the day, or run 5 miles. Which is easier for your generally sedentary, overweight individual?

psuLemon

SergeantSausage wrote: »

It doesn't matter. The only thing that matters is creating a calorie deficit.

For most folks, though, a 500 calorie defect in the kitchen is far, far easier that a 500 calorie deficit in the gym. You can cut out soda for the day, or run 5 miles. Which is easier for your generally sedentary, overweight individual?

Yep... and also taking into consideration the average person over reports calories burned and under reports calories consumed.

dramaqueen45

I think it's possible to lose on just exercise- my husband has lost about 16 pounds not really changing his diet but he took up walking daily and lifting as well as swimming. However I think it's much more difficult and slower to do it that way. I think it depends on the person, how high the metabolism is, etc. I have done aerobics 3-4 days a week for an hour each time and not changed my diet and lost nothing. I also know others who are religious about walking or going to zumba and they don't really watch their diets and they also lose nothing. So I think it can depend on the person, but really if you want to lose consistently- watch what you eat and track everything for the most success. My sister has lost about 40 pounds in a year but she is super addicted to title I boxing and goes almost daily. She doesn't really track calories but just tries to really limit simple carbs and stops eating at 7:00 p.m. (although she knows it doesn't really matter what time you eat- she just needs to have a "stop time").

Kalikel

Yes, of course exercise helps you burn more calories.

I don't know what this rule is, but I don't the rule is enforced, lol.

Sued0nim

Leyshinka wrote: »

Please help me understand why this is the general assumption to weight loss. I'll try to keep my thoughts simple using the example below:

A female athlete eats 2500 calories and burns 500 calories with exercise to maintain weight X. She stops her training and leads a sedentary life whilst still eating 2500 calories. Over time she gains weight until she reaches weight XY. She maintains this weight for a number of years. If she starts her athletic training again, burning 500 calories whilst still eating 2500 calories, my simple brain tells me that she would loose weight until she reaches weight X.

Is that not weightloss due 100% exercise?

yes but your athlete is on maintenance at 2500

if she brings back her exercise she will back at maintenance but at a higher weight

she has to cut calories - easiest in the kitchen

MandyBayma

More: if she eats 2500 and burns 500, she'll mantain her weight (in that scenario, a total of 2000 calories was just maintaining her weight in the beginning, right? Not making her lose weight). She would have to eat 2500 and burn 1000 in exercise, much harder than eating 2000 and burning 500.

To lose weight you have to create a deficit, and do it right. If you run all day long, you'll pass out, if all you eat is a super bacon burger with 2500 calories and nothing else all day, you'll be sick. You are what you eat, period. Exercise helps build muscle, which burns calories, but if you have to choose only one change to your lifestyle, choose eating healthy.

Poods71

You can lose weight with exercise alone but you have to do a lot. My hubby has always cycled but more mountain biking and casual rides. He has now been doing road biking, time trials and going to the velodrome. He eats loads and has lost 3 stone without even trying. I don't do so much exercise so diet is where it's at for me lol

mzjenn2u

You can't out exercise a bad diet.....maybe at first but eventually it will catch up with you

Muffie22

MandyBayma wrote: »

More: if she eats 2500 and burns 500, she'll mantain her weight (in that scenario, a total of 2000 calories was just maintaining her weight in the beginning, right? Not making her lose weight). She would have to eat 2500 and burn 1000 in exercise, much harder than eating 2000 and burning 500.

To lose weight you have to create a deficit, and do it right. If you run all day long, you'll pass out, if all you eat is a super bacon burger with 2500 calories and nothing else all day, you'll be sick. You are what you eat, period. Exercise helps build muscle, which burns calories, but if you have to choose only one change to your lifestyle, choose eating healthy.

But surely now that she weighs more her maintenance calories will be higher than in the beginning? So if she continued eating 2500 and burning 500 she should lose weight again (very slowly)?

Assuming you are eating at maintenance and don't change your diet at all, and then start exercising then you WILL lose weight. However, a lot of people will unknowingly increase their intake due to increased hunger from exercise, leading to no weight loss or even weight gain and frustration because they're putting in all this work in the gym and getting no where.

Also, lets say a large chocolate bar has 300 calories. If you're not counting calories you probably don't feel like it adds a lot to your daily intake because it's quick and easy to eat and doesn't really fill you up. On the other hand, a 140lb person may need to run consistently for half an hour to burn off the same amount of calories, which, if you don't usually exercise might be a very difficult task... you may even feel so exhausted afterwards that you reward yourself with a 'small treat' say... a chocolate bar? thus, without realising it you've completely wiped out your deficit.

That's why it's 80% diet, 20% exercise. Because it's easier to just not eat the chocolate bar in the first place. It's not a rule or anything, as long as you have a calorie deficit through exercise, diet or both you will lose weight. I know that if I wasn't tracking on mfp I'd gain so much weight through eating after exercising because exercise makes me ravenously hungry!

ndj1979

dramaqueen45 wrote: »

I think it's possible to lose on just exercise- my husband has lost about 16 pounds not really changing his diet but he took up walking daily and lifting as well as swimming. However I think it's much more difficult and slower to do it that way. I think it depends on the person, how high the metabolism is, etc. I have done aerobics 3-4 days a week for an hour each time and not changed my diet and lost nothing. I also know others who are religious about walking or going to zumba and they don't really watch their diets and they also lose nothing. So I think it can depend on the person, but really if you want to lose consistently- watch what you eat and track everything for the most success. My sister has lost about 40 pounds in a year but she is super addicted to title I boxing and goes almost daily. She doesn't really track calories but just tries to really limit simple carbs and stops eating at 7:00 p.m. (although she knows it doesn't really matter what time you eat- she just needs to have a "stop time").

possible yes, necessary, no ..

OP - the calorie deficit is what matters. Exercise is just an addend bonus if you want recomp, look good, have overall health, lift heavy things, etc...

brianpperkins

Leyshinka wrote: »

Please help me understand why this is the general assumption to weight loss. I'll try to keep my thoughts simple using the example below:

A female athlete eats 2500 calories and burns 500 calories with exercise to maintain weight X. She stops her training and leads a sedentary life whilst still eating 2500 calories. Over time she gains weight until she reaches weight XY. She maintains this weight for a number of years. If she starts her athletic training again, burning 500 calories whilst still eating 2500 calories, my simple brain tells me that she would loose weight until she reaches weight X.

Is that not weightloss due 100% exercise?

In your example eat 2500 calories - 500 exercise calories = 2000 net calories to maintain.

Eating at 2500 calories is above maintenance, resulting in ongoing weight gain until corrected.

Returning to 2000 net calories results in maintenance at whatever the weight is at that time.

To lose weight would require a deficit from 2000 calories.

sijomial

"Rules are for the obedience of fools and the guidance of wise men."
- Douglas Bader

Weight loss is 100% your calorie balance over time and there's different ways to achieve that to reach your goals. Add more exercise/activity, reduce your intake or a bit of both.

leggup

"A female athlete eats 2500 calories and burns 500 calories with exercise to maintain weight X." That means her net maintenance calories to keep weight X is 2000 calories. Yes, she will gain weight if she becomes sedentary and starts netting 2500 when her maintenance is 2000. Going back to netting 2000 calories will, theoretically, eventually drop her down to weight X. How long it takes will depend on whether X was really low to begin with, what's the difference between X and XY, and, an oft overlooked area... how much muscle she lost when she became sedentary, plus any other muscle she would lose in cutting weight (dropping from net 2500 to net 2000). Her new net maintenance calories could actually be 1900 due to muscle loss. Adding back exercise at a calorie deficit would not necessarily rebuild all of her muscle (we don't know her starting BF%, whether she lifted weights or was a marathon runner, etc).

TimothyFish

One problem that people who exercise have is that they tend to eat more when they exercise, so they won't actually lose weight. That being said, I find that it is very difficult to create a calorie deficit without exercise. It is possible, yes, but it is more difficult.

I think most people would be better off if they would focus more on exercise than on diet. When your goals are exercise based, you aren't thinking so much about having to cut out certain foods or some number of calories. Instead, you are thinking in terms of how you can go faster or perform longer. Your focus on food becomes a focus on fueling your workout rather than eating for pleasure.

Capt_Apollo

trust me, i tried to out train a bad diet. i'm a triathlete and sometimes lifter. i worked out often and hard, and my diet wasn't even that bad!!! but until about two months ago when i started being more mindful of what i put in my body, did i start dropping weight again after almost a two year stall.

ketorach

You can't outrun your fork. When I was half marathon training, I gained weight because I was so hungry all the time and apparently eating at a surplus.

ninerbuff

Regardless of what her weight is, a calorie deficit from current TDEE is needed to lose weight. A few years of being overweight also means a few years of age which usually is a reduction in metabolic rate. There are variables here that have to be considered with hormone balance as well.
But overall, as everyone has been mentioning exercise (while it can help create a calorie deficit) is for fitness and health. Diet is needed to be correct on calories to lose weight.

A.C.E. Certified Personal and Group Fitness Trainer
IDEA Fitness member
Kickboxing Certified Instructor
Been in fitness for 30 years and have studied kinesiology and nutrition