Feeling Full

Tomorrow is Thanksgiving and the temptation to over-eat is tremendous! (For those who are new to my blog and want to know more about turkey you can read last year's post here.) So I thought that the topic of satiety signals would be apropos. But first, how many of us are aware of the difference between hunger and appetite? Hunger is physiological, appetite is psychological. Many of us, probably me included, will continue to eat because of appetite, not hunger tomorrow. We will completely ignore our bodies and keep right on eating well past being full.

Satiety is the condition of being full, or at least of feeling full so that your know when to stop eating. In your body satiety is a set of physiological signals that come from your gastrointestinal tract to your brain; specifically the brain stem and hypothalamus by way of the vagus nerve. The hypothalamus is our body's regulator of food behavior - it tells us to keep eating or to stop eating. (We know that this occurs here because people who have injured their hypothalamus have difficulty regulating their eating behaviors.) But other things are occurring when we eat; hormones are produced (somewhere around 20-30, including insulin) which may also be telling the brain when you are full.

New research is suggesting that a naturally occurring family of fats derived from lecithin, called oleoylethanoamide or OEA, play a role in signaling satiety; OEA appears to "talk" to the vagus nerve inducing satiety and reducing food intake. OEA is a combination of oleic acid (omega-9 like is found in olive oil) and ethanolamine. Although studies are currently ongoing, and are being done on rats not people, some interesting findings are being reported. In addition to appetite suppression, OEA appears to encourage fatty acid catabolism and lower blood lipid levels.

Because many of the foods we eat at Thanksgiving are high in fat and sugar, and low in protein (well, excluding the turkey) and fiber we don't feel satiated for very long. Keep this in mind as you munch your way through the meal tomorrow and listen for your satiety signals!

Is That Natural?

Natural seems a simple enough word; the dictionary definition is simple: existing in or formed by nature. If only it were that simple when it comes to the food you buy. You see each governmental agency has its own definition, or lack of one and that can (and does) lead to quite a bit of confusion.

The Food & Drug Administration (FDA) in 1988 defined natural as: nothing artificial or synthetic has been added to or included in a food that would not normally be expected to be in the food. Since then the industry has asked numerous times for clarification and/or redefinition of the term "natural", but alas to date the FDA has refused.

The United States Department of Agriculture (USDA) uses a decision tree to determine the natural status of a food (well really just meat, poultry & eggs since those are under their jurisdiction). They ask the following questions:

1. Does the product contain an artificial flavor, coloring agent, chemical preservative, or any other synthetic or artificial ingredient? If the answer is yes, then the product cannot be labeled as natural.
2. Are the product and its ingredients minimally processed? If the answer is yes, then the product can be labeled as natural.

Seems like this is pretty straight forward - right? Well, no. Some of the problems here are with defining minimally processed. Does drying, roasting/cooking, lowering pH (adding an acid like lemon juice or vinegar), or pressure cooking cause a product to lose it ability to call itself natural? What about microbially fermented products like yogurt, cheese, beer or wine - are these natural? You get the point.

And if those weren't enough to cause confusion, the National Advertising Division of the Better Business Bureau had decided they want a voice in this discussion too. They define natural as depending on:

1. The origin of the ingredients
2. How the term "natural" is presented in the context of a challenged advertisement
3. And the reasonable customer expectation as to the meaning of the term "natural"

Ouch! No wonder there is so much confusion about such a simple little word. There is a growing amount of pressure by consumers to have terms such as "natural" standardized and believe me, the industry is on board with that. Sometimes the simple things in life just aren't that simple.

Sweet Is as Sweet Does

Sugar, that ubiquitous sweet substance we all love, is comprised of fructose & glucose (50%/50%) as you learned here. HFCS (high fructose corn syrup) is also comprised of fructose & glucose in a very similar ratio (55%/45% or 42%/58%). So why is HFCS vilified, sugar not and honey, agave syrup and evaporated cane juice all but ignored?

Both fructose and glucose have the chemical formula of C6H12O6, but have different configurations (where the atoms are located) and so have different sweetness levels and are metabolized differently. Fructose is absorbed through the wall of the small intestine directly into the bloodstream and taken up into the liver cells where it is converted into components indistinguishable from glucose and sometimes into glucose. A downside of each: glucose needs insulin to get into your cells, fructose doesn't, so it has a high glycemic response while fructose is more likely to elevate your triglyceride levels.

In sugar the monosaccharides fructose & glucose are linked, unlike in HFCS where they are not. Enzymes in your digestive system break down the links into the individual monosaccharides fructose and glucose which are processed identically to monosaccharides consumed separately. Since all of these products will end up as monosaccharides, it is impossible to say one is inherently better or worse for you.

In addition, the University of Washington Nutritional Science Program performed a study which showed that there was no direct link between the type of sweetener consumed and obesity. While the American Journal of Clinical Nutrition study results showed that cane sugar and HFCS have similar effects on hunger, fullness and food consumption.

Whether you consume sugar (50% fructose), HFCS (42 or 55% fructose), honey (53% fructose), agave nectar (56 -92% fructose) or evaporated cane juice (45% fructose), your body is going to treat them all the same. That is not to say that there is not a difference between eating a piece of fruit (a pear for instance) or a candy bar. While your body may not distinguish one fructose molecule from another, the pear has water (a diluent), fiber, vitamins and minerals which the candy bar most certainly does not.

So, enjoy your sweets in moderation and don't get caught up in all the hype; we could all do better at consuming less sugar in any of its forms!

UPDATE! American Journal of Clinical Nutrition Supplements:

1. High Fructose Corn Syrup: Everything You Wanted to Know, But Were Afraid to Ask
2. Straight Talk About HFCS: What it is and what it ain't
3. HFCS: Is This What's For Dinner?
4. Endocrine & metabolic effects of consuming beverages sweetened with fructose, glucose, sucrose or HFCS
5. HFCS, energy intake and appetite regulation

Are you a Flexitarian?

You know what a vegetarian is, and if you watch Wendy's commercials you've heard the term they coined - meatitarian, but what is a flexitarian? The American Dialect Society defines flexitarian as: a vegetarian who occasionally eats meat. My industry takes a bit broader view of the term.

To the food industry a flexitarian is a part-time vegetarian; someone who may eat vegetarian meals from 1-4 times per week. Since so many of us are trying to eat more healthfully, a large portion of the population probably meets this definition. In fact, given that humans are omnivores, it really is no surprise that we don't eat meat at every meal. Flexitarian meals may fall into multiple vegetarian categories too, like lacto-vegetarian (contains dairy products), ovo-vegetarian (contains eggs), ovo-lacto-vegetarian (contains both dairy and egg) and total vegetarian (or vegan).

Since health is often the primary driver for this type of eating, substanitive, hearty proteins that are filling are usually preferred. A flexitarian often chooses substitute protein sources like tofu, whole grains, and legumes to replace the traditional center of the plate chicken, beef, pork or fish. We can all use more vegetables, fruits, and whole grains in our diet regardless of how we categorize ourselves - so eat well and be well!