Can Low Carb Dieters Eat All They Want And Still Lose Weight?
“The Atkins Nutritional Approach counts grams of carbohydrates instead of calories… If you are losing weight, there is no need to concern yourself with counting calories. ”
Source: atkins.com
You might be doubtful and chances are that mainstream diets are the reason. Of course you couldn’t avoid opinions like the below Q&A posted by Health Care Reality Check:
Q: Can a person eat unlimited calories, and still lose weight, as long as they severely restrict carbohydrates?
A: No, she can not. The basis of ketogenic diets, such as the Atkins Diet, is a severe restriction of carbohydrate calories, which simply causes a net reduction in total calories. Since carbohydrate calories are limited, intake of fat usually increases. This high fat diet causes ketosis (increased blood ketones from fat breakdown), which suppresses hunger, and thus contributes to caloric restriction. — Ellen Coleman, RD, MA, MPH
Is this a correct answer?
Let’s first discuss whether it’s a correct question. Or, rather, is this the real question so frequently asked by dieters. In my experience, this in fact sounds a little bit different but this makes ALL the difference.
This is what real dieters ask:
Q: Can low carb dieters eat all they want, and still lose weight as long as they only eat allowed foods?
A: Yes, they can. The basis of ketogenic diets, such as the Atkins Diet, is a restriction of carbohydrate-containing foods in favor of fat and protein containing foods, which causes the state of ketosis resulting in significant decrease in appetite. Since appetite decreases, most of low carb dieters consume significantly less calories WITHOUT INTENTIONAL CALORIE RESTRICTION.
Is there scientific evidence?
There is.
Study #1 by: Bassett Research Institute in Cooperstown, NY and Durham (N.C.) Veterans Affairs Medical Center.
Reported: Proceedings of North American Association for the Study of Obesity, Oct. 29, 2000, Long Beach, Calif.
Who participated:
18 obese men and women with 30 or more pounds to lose.
Average calorie intake before the study: 2,481 calories a day
Method:
Dr. Atkins’ Book, the “New Diet Revolution” used as instruction for the dieters.
Results:
1. Calorie intake during the most restrictive induction phase (when only 20 g of carbohydrates were allowed) was 1,419 calories a day on average and weight loss was more than 8 pounds on average.
2. Calorie intake during the ongoing weight-loss phase (when carbohydrate intake is being increased gradually, by 5 g a day) dieters ate an average of 1,500 calories a day and lost an additional 3 pounds in two weeks.
3. The calorie reduction was attributed almost completely to carbohydrate abstaining. Intake of fat and protein remained practically the same as before the diet.
4. After 6 months on Atkins diet, 41 overweight people lost an average of 10% of their weight. Most dieters lowered their cholesterol by 5%, but there were a few whose cholesterol increased.
5. 20 out of 41 dieters continued the program, and kept the lost weight off for more than a year.
Study #2 by: Harvard School of Public Health.
Reported: American Association for the Study of Obesity, October 16, 2003
Who participated: 21 overweight volunteers.
Two groups were randomly assigned to either lowfat or low-carb diets with 1,500 calories for women and 1,800 for men; a third group was also low-carb but got an extra 300 calories a day.
Method: All the food was prepared at a restaurant in Cambridge, Massachusetts. Note that most earlier studies including the above Study #1 simply gave out diet plans.
So in this study, dieters were given dinner and a bedtime snack as well as breakfast and lunch for the next day, which made the setting a carefully controlled one. Foods were mostly fish, chicken, salads, vegetables and unsaturated oils. Red meats and saturated fats were limited (as opposed to traditional Atkins menus.)
All meals looked similar but were cooked to different recipes. The low-carb meals were 5% carbs, 15% protein, 65% fat. The low fat group got 55% carbohydrate, 15% protein, 30% fat.
Results:
1. All dieters lost weight, but those on low carb diet lost more than the low fat group — even while consuming MORE calories:
- Group on lower-cal, low-carb diet lost an average of 23 lbs.
- Group on same-calories low-fat diet lost an average of 17 lbs.
- Group on extra 300 calories, low-carb diet lost an average of 20 lbs.
2. Over the course of the study, the group of low carb dieters who got an extra 300 calories a day consumed extra 25,000 calories. That should have added up to about seven pounds. But for some reason, it did not.
Discussion:
“It doesn’t make sense, does it?” said Barbara Rolls of Pennsylvania State University. “It violates the laws of thermodynamics. No one has ever found any miraculous metabolic effects.”
So it violates the laws of thermodynamics, huh? Not so fast! When it comes to calorie counting, the “calorie is a calorie” concept is very deceiving.
Let’s see what we count when we think we count calories. When you burn a piece of wood in a stove, you can directly measure how much heat energy it produces. Then you can claim that you know how many calories a piece of wood contains, right? Not exactly. You should specify what kind of wood it was, dry or wet, how you burned it, etc. Because if you spent another material to start the burning, you should subtract these calories from the total; if the wood was wet you should take into account the calories that the water evaporation took. So even with a piece of wood, it’s not that simple.
Now look at a piece of food. You know how they tell how many calories it contains? Same way they talk about a piece of wood in a stove. It’s the calorie number that the food would produce by being burnt in a stove.
Then in addition to the wood’s calorie estimation (that takes into account the dryness, etc.), you should add many more circumstances: how hard should one chew it before being able to swallow, how hard one’s enzyme system will have work to digest it, will it influence the hormones in charge of fat storing? What about its effect on the hormones in charge of fat burning?
Which chain of reactions will it trigger, activity-wise or metabolism-wise? Will it make one sleepy, thus conserving the energy? Ot will it make one jumpy, thus wasting the energy?
Study #3 by: Laboratory of Applied Physiology, Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan
Reported: J Clin Endocrinol Metab. 2003 Dec;88(12):5661-7
Method:
Healthy boys, aged 8-11 yr, were examined for resting energy expenditure and the thermic effect of a meal, which were measured for three hours after a same-calorie but high-fat or a high-carb meals.
Results:
There was no changes after high carbohydrate meals but there was an increase in resting energy expenditure after a high-fat meal.
If the researchers in the Study #2 would have measured resting energy expenditure and the thermic effects of the meals, they would probably have registered the same changes. Then everybody would make a sigh of relief: none of the laws of thermodynamics have been violated: yes, the low-carb dieters COULD INDEED eat more calories and lose more weight than the low-fat group while violating no physical laws because — they just burnt more, all the time, even at rest. It’s that simple.
About the Author
Tanya Zilberter, PhD, is a researcher, health educator, exercise physiologist, and scientific journalist.
In health sciences since 1972, Dr. Zilberter authored several hundred scientific and popular publications, including four print books and more than a dozen of eBooks.
Written By: Tanya Zilberter, PhD