While Slim-Fast drinks don’t clearly have any gluten-containing ingredients in the recipe, such as wheat flour, they could have hints of gluten that result from the way they are manufactured. If you have celiac disease or are gluten sensitive, the drinks might upset your stomach. If you don’t see the term “gluten-free” spelled out on the label of any product you prefer, it’s likely something that you’ll want to avoid.
Pre-Made Drinks vs. Powder
Neither the pre-made Slim-Fast drinks nor dried powders are labeled “gluten-free.” The only allergens listed on the ready-to-drink shakes are milk and soy, but these two allergens are not listed on the Slim-Fast powders. On most of the powdered-drink products, you see the phrase “may contain wheat” which lets you know that the final product could contain some gluten.
Meaning Behind “Gluten-Free”
Gluten-free labeling is optional for food manufacturers -- the U.S. Food and Drug Administration doesn’t require it. However, if companies choose to put “gluten-free” on their label, they have to follow strict guidelines. The final product can't have more than 20 parts per million of gluten. Thus, even though some Slim-Fast drinks don't directly contain wheat, barley, rye or related grain, they might not meet the strict standards the FDA has set forth, because of how the products are manufactured.
Gluten and Cross-Contamination
Makers of Slim-Fast produce a variety of foodstuffs, ranging from meal-replacement bars and snacks, all the way up to their drink products. Because of the ingredients that enter the facilities, some of the equipment used in manufacturing might leave traces of gluten, resulting in cross-contamination. This is why some drink mixes say “may contain wheat” on the label. Wheat isn’t supposed to be in there and isn’t listed in the recipe, although some wheat -- and thus gluten -- could sneak into the final drink.
Slim-Fast drinks and powders do contain maltodextrin, which is a controversial ingredient for those who cannot have gluten. Maltodextrin is a concentrated dried starch that food producers use as a filler to add texture and thickness. In the United States, maltodextrin is typically derived from corn or potatoes. In other parts of the world, however, it is sometimes made with barley or wheat. This is why maltodextrin is likely safe if the food is manufactured in the United States. If you go elsewhere or buy your products at an international market, maltodextrin could be the cause any gastrointestinal problems you experience.