Diet alone will not likely lead to significant weight loss

Apr 13, 2010

Newly-published research by scientists at Oregon Health & Science University demonstrates that simply reducing caloric intake is not enough to promote significant weight loss. This appears to be due to a natural compensatory mechanism that reduces a person's physical activity in response to a reduction in calories. The research is published in the April edition of the American Journal of Physiology - Regulatory, Integrative and Comparative Physiology.

"In the midst of America's obesity epidemic, physicians frequently advise their patients to reduce the number of calories they are consuming on a daily basis. This research shows that simply dieting will not likely cause substantial . Instead, diet and exercise must be combined to achieve this goal," explained Judy Cameron Ph.D., a senior scientist at OHSU's Oregon National Primate Research Center, and a professor of behavioral neuroscience and obstetrics & gynecology in the OHSU School of Medicine, as well as a professor of psychiatry at the University of Pittsburgh.

To conduct the research, Cameron and OHSU post-doctoral fellow Elinor Sullivan, Ph.D., studied 18 female rhesus macaque monkeys at the Oregon National Primate Research Center. The monkeys were placed on a high-fat diet for several years. They were then returned to a lower-fat diet (standard monkey food) with a 30 percent reduction in calories. For a one-month period, the monkeys' weight and activity levels were closely tracked. Activity was tracked through the use of an activity monitor worn on a collar.

"Surprisingly, there was no significant weight loss at the end of the month," explained Sullivan. "However, there was a significant change in the activity levels for these monkeys. Naturally occurring levels of for the animals began to diminish soon after the reduced-calorie diet began. When caloric intake was further reduced in a second month, physical activity in the monkeys diminished even further."

A comparison group of three monkeys was fed a normal monkey diet and was trained to exercise for one hour daily on a treadmill. This comparison group did lose weight.

"This study demonstrates that there is a natural body mechanism which conserves energy in response to a reduction in calories. Food is not always plentiful for humans and animals and the body seems to have developed a strategy for responding to these fluctuations," added Cameron. "These findings will assist medical professionals in advising their patients. It may also impact the development of community interventions to battle the childhood obesity epidemic and lead to programs that emphasize both and exercise."

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bottomlesssoul
not rated yet Apr 13, 2010
The body is amazingly robust in remodeling itself to maintain environmental fitness of purpose. Since the local environment is determined by hundreds of variables, adjusting one or two will not have much of an impact.

Obese people are 'fit' for their environment and behaviors. I used to be in such a fit state. I changed my diet, the amounts I eat, the amounts I have readily available (none to account for my lack of self control) and moved to a tropical island off of Cambodia where I have to walk 2 km to get breakfast. I am fit for this environment now with a BMI of 22.

I had to change dozens of variables for the rest of my life to change my fitness level from western obese to hard-body athlete.
Bloodoflamb
1 / 5 (1) Apr 13, 2010
Sufficient caloric restriction will lead to weight loss. Always. It's this thing called conservation of energy.
kraisar
not rated yet Apr 13, 2010
That's true, but I suspect for most people they don't reduce caloric intake enough to trigger that kind of loss, rather just a moderate reduction that the body can compensate for by slowing the metabolism down. Combined with exercise it will help keep the metabolism up and also burn the calories. And obviously at some point if you take in too few calories the metabolism can't get any lower so you loose mass. Really not sure what is surprising in all this as I thought it was well known.
dsl5000
not rated yet Apr 13, 2010
Dieting (in this definition: lower caloric intake) is stupid...unless you are one of the few who are morbidly obese where you really can't exercise (I've seen those people).

Exercise is best, objective isn't to lose weight but to increase strength so that it improves the quality of life.

Look at Michael Phelps, last time my friend saw him, he ate at Ihops, Phelps was gouging pancakes like no tomorrow. He eats over 10000 calories. Low caloric diet? hahaha

Though good diet is beneficial for proper growth (though this article isn't talking about balanced diet imo)

btw i thought this was common sense. Oh well
dsl5000
not rated yet Apr 13, 2010
In addendum, i always throw this to my friends when they can't decide between diet or exercise.

How many fat marathoners have you seen (people who have completed the marathon)?

:)
winthrom
not rated yet Apr 14, 2010
I assume the monkeys eating a high-fat diet were eating real fats. I also assume they became obese since that is what high calorie diets lead to over several years. Since fat monkeys are not likely to be athletic, and the 30 percent reduction in calories via a switch to monkey chow was still sufficient for obesity maintenance, the results are unpredictable and do not lead to any valid conclusions. Unless the monkeys were put on a reduced high-fat diet (but with 30% less calories) the change in diet foods may have been the source of lower activity.
david13579
not rated yet Apr 14, 2010
This is not true. I lost about 50 pounds just by eating less with not exercise at all.
bottomlesssoul
not rated yet Apr 14, 2010
Dietary restriction will NOT lower weight. The body will alter your behavior and make you rest or seek high calorie foods. That is why it takes a multi-prong approach. Many processes are leading to weight gain, and many processes are needed to reduce weight.

Anecdotal stories aside.
Husky
not rated yet Apr 14, 2010
ACtually, i advise people to do exercise first for 2 months , while maintaining current calorie intake, even before starting dieting, this prevents metabolic shutdown and helps you develop fat burning pathways through exercise without feeling tired or unable to max out on your interval training session because you ate too little. As a bodybuilder, after a layoff, first thing i do is 3 weeks of rigorous aerobic exercise before i hit the weights again, this helps me to be able to eat more, crank up my BMR, so that when i cut down on aerobics and switch to hoisting iron i can still eat all out without too much turning into fat
Husky
not rated yet Apr 14, 2010
but remember, not all calories and fats are created equal, pay close attention to glycemic index, timing and adjusting the complexity of your carbs, in accordance to pre- post exercise etc and using the right kind of fats, like flaxseed instead of industrial palmoil is a science in itself.
Neebone
not rated yet Apr 14, 2010
Sufficient caloric restriction will lead to weight loss. Always. It's this thing called conservation of energy.


Not true. Yes, conservation of energy applies, but it doesn't tell you what how the equation balances out.

If you reduce calories and do no extra movement above current, the body should regulate itself to that reduction in calories by inducing lethargy (for example). The reverse is also true. An increase in calories should illicit a feeling of 'energy' and thus lead to an increase in activity and thus no weight gain (up to a point of course).

But as has been said not all calories are created equal, and there are different biological effects depending on the ratio of macro nutrients ingested, even if the overall calorie count remains the same (a high carb/low protein diet vs a high protein/low carb diet for example).
Bloodoflamb
not rated yet Apr 14, 2010
So if I go from eating about 2300 to 2500 calories a day, to roughly 1500 I'll just become sleepy, and won't lose weight? Sounds like you're full of it! There are basic body functions that require a certain amount of energy to maintain no matter how inactive you are. It's called a BMR, and human beings almost NEVER function at just the BMR, since most human beings don't sleep all day every day.
david13579
not rated yet Apr 14, 2010
Like I said, I lost over 50 pounds with no exercise whatsoever and I lost them in about 6 months. It was a really bad idea but it did work.
trekgeek1
not rated yet Apr 14, 2010
I'm no trainer, but here's what I've picked up over the years.

1.) Radically reducing calories will result in weight loss because of conservation of energy. The weight will return quickly when calories are restored. Crash diets are bad.

2.) Yes, moderate caloric restriction will result in weight loss slowly, just like the article said.

3.) Diet + exercise = best results. JUST LIKE THE ARTICLE SAID.

Please read and comprehend the article before commenting. It never said that caloric restriction alone would not reduce weight, it said it would not reduce weight if you change your activity level accordingly. If your busy schedule dictates a certain activity level, caloric restriction will work.
bfast
not rated yet Apr 14, 2010
I appreciate this article. Medical science's calory counting simplicity has been a dismal failure. If we are to get past the weight epidemic we are going to have to take a much more wholistic approach to weight loss, factoring in things such as how a person feels.
CSharpner
not rated yet Apr 14, 2010
I lost 60 lbs by doing nothing but eating less. I did zero exercise aside from what's necessary to move from computer chair to fridge to car and back. It's simple physics: Your body outputs mass. As long ans you input (eat) less than that mass, you'll have to lose weight. It's of course healthier to exercise, but it's definitely NOT necessary to lose weight.
doctorkim
Apr 14, 2010
This comment has been removed by a moderator.
david13579
not rated yet Apr 14, 2010
I go to the regularly. I've "kept it off" for a long while now.
doctorkim
Apr 14, 2010
This comment has been removed by a moderator.
magpies
not rated yet Apr 18, 2010
Changing the way I eat has made me gain weight why in the world wouldn't it make me lose weight?

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