Preventive Medicine Column

Dr. David L. Katz

There is a range of opinions regarding almost everything about weight loss.  People differ on what diet is best, what supplements are best, how important exercise is, which lotions, potions, pills or programs work and which don’t.  Even the relevance of calories has been challenged, although as I have noted on other occasions, that’s an argument with Einstein, Newton, and the laws of physics.  I would certainly tread carefully on such hallowed ground.

There is, though, one area of universal agreement.  If you want to lose weight, you need to eat less.  On some diet plans, it’s just plain less food.  On others, it’s less of certain foods.  But inevitably, something about dietary intake has got to give.

The basic problem with eating ‘less’ has to do with the obvious issue: less than what?  In general, the answer comes down to: less than you want.

In a nut shell, that is why all diets tend to work in the short term, and almost none tends to work in the long term.  People are willing to ride the draft of a New Year’s resolution, or tough it out, or aim for a special event over the span of a few weeks.  But few people are willing to practice lifelong asceticism.  And that, along with a constant state of hunger, is what eating less than you want for the rest of your life is.

This may be the very reason that personal weight control, and control of the obesity epidemic, have proven so elusive.  The choice has been between thin, but hungry and unsatisfied; or full and satisfied, but not thin.

There is one way to fix this problem: fill up on fewer calories.  In a word, enhance satiety.

Satiety refers to achieving, and maintaining, a feeling of fullness.  Satiety is generally what makes use decide we’ve had enough to eat.

We’ve long known that the inner workings of satiety are complicated, and in fact, are finding more complications all the time.  There are stretch receptors in the stomach, for instance, that provide a satiety signal based solely on the food volume.  But the stomach is also an endocrine (hormone producing) organ, and releases the hunger-stimulating hormone, ghrelin.  A whole cascade of hormones influences hunger, appetite, and satiety- with the stomach, esophagus, intestines, pancreas, liver, the hypothalamus brain region, and to some extent adrenal glands all in on the act.

With expanding knowledge of the cascade involved in producing, and preventing, satiety, it was just a matter of time before the food industry started applying this knowledge in earnest to new product development.  According to the Wall Street Journal (1/25), that’s just what the Nestle company plans to do.  Scientists at Nestle, one of the world’s largest food companies, are at work designing foods to interact with the hormones that underlie appetite, and get the system to register “full” on fewer calories.

Since I am a staunch defender of the concept that weight control is fundamentally about calories in versus calories out, I am very much a proponent of finding ways to help people fill up on fewer calories.  But I am not equally enthusiastic about all means to those ends.

Nestle, for example, is exploring modifications to oils that make them digest more slowly; and modifications to food that cause them to delay stomach emptying.  These reformulations could be helpful, but we will need to know about any unintended consequences.  Would such oils be heart-healthy, or not?  The best known “modified” oils we have in our food now are hydrogenated oils, which gave us the now notorious trans fat.  This could be a precautionary tale.  Will foods that delay gastric emptying be entirely safe for the lining of the stomach?

Time will tell, but we should be cautious about greater satiety through 21st century food engineering.  On the other hand, we should be open to it as well.  I am aware, for example, of a product called PGX®, made by Natural Factors, a Canadian supplement company.  The product is just a slightly modified kind of dietary fiber, called glucomannan.  But the slight modifications make very small amounts of PGX produce the same fullness as much larger amounts of glucomannan.  In addition, studies show that PGX stabilizes blood insulin and glucose.  The science available thus far suggests a product like PGX could be extremely useful in making functionally enhanced foods that offer a short cut to satiety, and health benefits into the bargain.

So we should all look on with both interest, and caution, as Nestle, and other food industry giants, explore ways to help us fill up on fewer calories.  But there is no need to wait for the products of their R&D to start applying the strategy right now.

Foods with a high fiber content help us fill up on fewer calories.  So do foods with a high water content, and volume.  Foods that keep flavors simple and avoid combinations of sweet, salty, and savory also foster satiety.  So do foods with a low glycemic load, and foods with high quality protein.

Many of the most nutritious foods, direct from nature, provide most or all of these attributes: vegetables, fruits, beans, lentils, nuts, seeds, whole grains.

Filling up on fewer calories means portion control and satisfaction can coexist- and that makes lasting wait control much more accessible.  In fact, it’s pretty much having your cake, and eating it, too.

Modern food science may be able to bake this cake in the form of functionally enhanced foods, and it will be interesting to see how they do.  But don’t overlook the fact that nature has had the recipe all along.




Dr. David L. Katz;