Hungry? Eat Protein!
Arne Arstrup writes in the American Journal Of Clinical Nutrition that telling fat people to eat less and exercise more doesn't do the job:
This simplistic strategy assumes that humans have conscious control over appetite and body weight regulation, which is certainly not the case for most people; if it were true, there would be no overweight or obese people. I have never met an obese patient who has worked hard to become obese and to maintain an excessive body size. We need to acknowledge that our regulatory systems are geared to prevent depletion of body energy stores and undernutrition effectively, whereas the systems that reduce appetite and increase energy expenditure during periods of excess availability of foods are easily suppressed by palatability and by the social, psychological, and rewarding aspects of foods.In the past, when people expended plenty of calories just by going about their daily business, it was possible to remain slim while eating a diet with nearly any nutritional profile. The problem nowadays is that many people are extremely sedentary, which makes it possible to overeat even when dietary intakes are relatively small. For example, it is easy to prepare tasty, filling meals with drinks for an active person who needs {approx}2500 kcal/d, but it is difficult to do the same for a sedentary person who needs only {approx}1800 kcal/d. This is why the current focus of science is to increase the satiating power of the diet, so that people feel full with fewer calories.
He points to Atkins and other protein-heavy diets as a likely solution:
In this issue of the Journal, Weigle et al (3) showed that an increase in dietary protein from 15% to 30% of energy and a reduction in fat from 35% to 20%, at a constant carbohydrate intake, produces a sustained decrease in ad libitum calorie intake and results in significant weight loss....Weigle et al's results clearly showed that protein is more satiating than is fat, and previous studies have shown that protein is more satiating than is carbohydrate (4). Moreover, diets with a fat content fixed at 30% of calories produce more weight loss when high in protein (25% of energy) than when normal in protein (12% of energy): 9.4 compared with 5.9 kg after 6 mo; after 1 y, evidence was found to suggest that the high-protein diet, independent of the loss of total body fat, resulted in a significant loss of visceral fat (5).
Should we advise overweight and obese patients to increase their protein intakes from 10–20% to 20–30% of calories and reduce their intake of fat and carbohydrates correspondingly? If fat intake is fixed at {approx}30% of calories, there is still plenty of room for carbohydrates to make up 40–50% of the calories. It is preferable to replace sugars from soft drinks with protein from low-fat milk, high-fat meat and dairy products with the lean versions, and possibly white bread and pasta with lean meat, without reducing the intakes of fruit, vegetables, and whole-grain products. Should we advise the public to increase their intakes of meat and dairy products? The answer depends on the potential adverse effects of a high-protein diet.
The guidelines from the Institute of Medicine allow for the inclusion of higher amounts of protein than previously recommended in a healthy diet (6). This institute concluded that there is no clear evidence that a high protein intake increases the risk of renal stones, osteoporosis, cancer, or cardiovascular disease.
Well, here are investigative science journalist Gary Taubes' comments -- exclusive to this blog! -- on the Arstrup piece:
On the other hand, he's simply wrong about the mechanisms. It's got nothing to do with satiating power. Carbohydrates promote fat accumulation, via insulin. That's one of the primary things insulin does. So it's not that protein or fat prevent obesity, it's that refined carbohydrates, starches and, particularly, sugar cause it. The weird thing is that the science was well worked out 50-years-old, and these people are simply unaware of it. (On the other hand, if they actually paid attention to their history, I wouldn't have a book.)
FYI, Taubes is one of the top investigative science journalists out there. He wrote the NY Times Mag piece that relaunched the Atkins Diet craze: What If It's All Been A Big Fat Lie, and The Soft Science Of Dietary Fat for the journal Science. He's working himself to the bone on his book -- which should revolutionize the way Americans eat -- and that's not hyperbole, either.
If Mr. Taubes doesn't mind a quick question or two (and is available): If I read the comment correctly, Mr. Taubes says that fat and protein are better than carbohydrates because of the effects of carbohydrate intake on insulin (and related systems). First, how does this account for the claimed fact (at least, this seems to be what the article implied) that people with higher proportions of protein in the diet actually eat less? Second, how does that account for the effect of increasing protein intake relative to fat intake while holding carbohydrate intake constant? Thanks much for your answers.
Jadagul at July 13, 2005 4:52 AM
I'm not Taubes, but I agree wholeheartedly with his approach, and will definitely buy his book for myself and some friends of mine when it comes out.
I'm not the expert that Taubes is, but in case he's not available, I believe that he was talking more specifically about refined sugars. And I can explain why. I'll keep it simple. Refined sugars and starches (table sugar, white flour, for instance) have been stripped of the fiber that slows the absorption process in your digestive system. Without the fiber, the sugars and starches go into your system fast, fast, fast, causing the pancreas to produce a very high amount of insulin so you can absorb the sugar. (This condition, by the way, is given the very logical name hyperinsulinism.)
Not only do the excess calories (which are far more than you can use at once) get turned to fat, but the subsequent absorption of all that sugar wipes all the available carbohydrates from your blood stream. As carbohydrates are energy for your body, this produces the crash following the sugar rush. This in turn, like a drug, makes you crave more sugar for more energy. You go and indulge your sweet tooth with more refined sugar and starches and the cycle repeats, and you become obese as you absorb and store more calories than your body needs.
Naturally occurring sugars (with a few exceptions) are much more slowly absorbed. Apples, for instance, have a fair amount of sugar, but are also high in fiber. Fiber, fat, acidity in foods (such as vinegar sourdough bread) all slow down the absorption of carbohydrates. An apple's sugar is absorbed slowly and is a more consistent supply of energy, not a huge influx of more sugar than you can possibly use that will get turned to fat, but a steady flow in small amounts that you can actually use.
Some of you may be thinking that if sugar without the fiber causes hyperinsulinism (and consequently obesity), then fruit juices (apple juice, orange juice, grapejuice, etc.), without the fiber of the whole fruit, produces hyperinsulinism, too. You'd be correct. Eat your fruit, don't drink it. The one exception I know of is tomato juice which comes with a good amount of fiber. It's why my favorite drink is V8.
Lesson over. If Taubes is available, he can add or correct anything he cares to. I'm a personal trainer, and while we're expected to know a bit about nutrition, we are legally prohibited from prescribing diets.
Patrick the cynic at July 13, 2005 5:31 AM
I appreciate the explanation, Patrick, but it still leaves me with a couple of specific questions. First, it still doesn't explain why exchanging fats for proteins, holding carbs equal, leads to a reduction in the amount that you eat. I'm sure there's a good explanation, but I'd like to have it.
Second, your explanation of the mechanism by which eating refined sugar leads to fat is actually different from what Mr. Taubes says in the brief excerpt in Amy's post. The original cited article suggests that "sugar satiates less than fat," which sounds to me like a layman's version of the explanation you just gave me. Mr. Taubes, however, responds that "he's simply wrong about the mechanisms. It's got nothing to do with satiating power." That seems to directly contradict your claim that "This in turn, like a drug, makes you crave more sugar for more energy. You go and indulge your sweet tooth with more refined sugar and starches and the cycle repeats, and you become obese as you absorb and store more calories than your body needs."
What I'd read before had indicated that it was a bit of both; I know for a fact that sugar doesn't keep me full at all, which is why I actively look for foods with high fat content (Need lots of fat and protein to stay full; sugar doesn't cut it). This article would drive me more to protein and less to fat; but both your explanation and my experience indicate that Mr. Taubes's bald rejection of satiation as "having nothing to do with it" is, at least, an overstatement. However, I'm very open to being corrected.
Jadagul at July 13, 2005 7:15 AM
Mr. Taubes, sadly, is not available. He's something of a scientific rock star, and he's home in his writer's garrett, finishing the book. I suggest you take a look at the two articles I linked.
A layperson's tip (but one who reads a lot in this area): If I eat any sugar or carbohydrates, I make sure they're combined with fat, to slow down the digestion of it. ie, yeast donuts -- good! White bread plain, bad! Somebody recently asked me how I keep getting thinner. My answer: Great donut store near me. They didn't like that one bit. Truth is, I eat like a French girl. Lots of meat and vegetables, but high quality and small portions (by meat, I mean fish and chicken, too)...and a bit of bread (donuts or croissants), lots of cheese, etc., and small, very fine desserts. Buy a $3 Swiss chocolate bar, and it will last you three weeks. A bargain! Especially over that waxy crap from Hershey's!
Amy Alkon at July 13, 2005 8:00 AM
Thanks, Amy. I suspected as much, but it was worth a shot. I'll read the articles you linked after I get some sleep (as far as I'm concerned, it's still Tuesday).
Jadagul at July 13, 2005 8:08 AM
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