By Jennifer Nelson, M.S., R.D. and Katherine Zeratsky, R.D.
New York City restaurants have been phasing out artificial trans fats over the past 18 months and the city-wide ban took full effect on July 1st.
All foods containing artificial trans fat now must have less than 0.5 grams of trans fat per serving. Packaged foods served in the manufacturer's original packaging are exempt.
Similar measures have been passed in other cities and states.
But what are chefs and cooks using to make their muffins and doughnuts moist, breads crisp and light, and pastries flaky? And, are they healthy?
Food manufacturers are basically taking four approaches to reducing trans fats — going back to traditional/natural fats, making blends of fats, interesterification and enhancing the traits of fats. Each has positives and negatives.
Traditional/natural fats include lard (pork fat), tallow (beef — and sometimes sheep — fat), and butter. Prior to about 1910 and the advent of shortening these solid fats were used for frying and in baked goods. These fats are mainly saturated though — and saturated fat is second in line to trans fat in terms of clogging arteries. These days, most lard that you purchase has also been "hydrogenated" — so also contains trans fats.
Fat blends include mixtures of healthy unsaturated oils like olive or canola with smaller amounts of trans fat such as partially hydrogenated soybean oil. Or there are blends of healthy oils with highly saturated plant oils such as coconut or palm. This allows manufacturers to use less/no trans fat. These blends are lower overall in saturated fat than lard, tallow and butter.
Interesterification is a chemical or enzymatic process that switches out undesirable fatty acids. Soybean oil, for example, naturally contains a mixture of saturated, mono- and polyunsaturated fatty acids. Through interesterification, saturated fatty acids can be replaced with healthier fatty acids — and the resulting product is more like what we're used to. However, some studies have shown that these fats may be harmful in other ways including lowering insulin levels, increasing blood sugar, as well as adversely affecting good cholesterol.
Trait-enhancing of plant fats via natural selection (hybridization) or by genetically modifying the plant can breed out undesirable fatty acids and increase more of the desirable ones. However, we're still a few years away from having such products readily available in our food system. We're also going on faith that these plant fats will be safe and healthy.
What to do? Since fat is high in calories, I'm going to keep it in check — no matter the source. I'm going to choose to use small amounts of vegetable oils — especially those that are predominantly monounsaturated like olive and canola. Finally, I'm going to use food labels including asking for nutrition information for restaurant menus. My eye will look first at total fat (keep it low), then trans fat (but zero can mean up to 1/2 gram/serving), then saturated (keep it low, too).
It's going to be a numbers game for a while until we can sort this out. Thoughts?
- Jennifer
source : mayoclinic.com
