DISCLAIMER:This has been my PERSONAL experience:
Dannon "ACTIVA", has done a GREAT job marketing the healthy effects of yogurt. I have taken their "challenge" and personally found it lacking. The servings sizes are very small, comparatively expensive per ounce, low in protein, high in sugar and just don't work for my needs. I will be the first to tell you my digestion is different from the VAST MAJORITY of people, because of the physical changes to my digestive tract from the bariatric surgery.
If you think "ACTIVIA" is good for you and aids in "regularity" try some FAGE "GREEK STYLE" yogurt...http://www.fageusa.com/products.aspx#/products/zero
or go to KROGER (if they are in your area) and get some of their CARBMASTER yogurt....
FAGE is EXPENSIVE @ about $2 for each of their smallest servings, but also has about 20g of protein in a 6 oz cup and only 120 cals....ZERO fat and 9g "sugar" for the plain, 0% fat....You flavor it, your choice...you will know it is working in about 2 days if you eat one a day.
KROGER, Carbmaster yogurt is the best tasting....cost is $0.41 per 6 oz cup. ...comes in several flavors, but the VANILLA is the BEST and can be modified with some fruit if desired, but why, the best tasting vanilla I have ever tasted! Calories 80
Total Fat 1.5g (Saturated 1.0g)
Potassium 90mgTotal Carb 4g (Fiber 1g, Sugars 3g)
Vitamin A 6%, Vitamin C 0%, Calcium 35%, Iron 0%, Vitamin D 15%
Ingredients: water, milk protein concentrate, whey protein concentrate, cream, modified corn starch, glycerine, natural and artifical flavor, salt, gelatin, tricalcium phosphate, malic acid, phosphoric acid, pectin, agar, sodium citrate, sucralose, acesulfame potassium, annatto and turmeric extract (for color), vitamin a palmitate, vitamin D3, active cultures with L acidophilus and B. bifidum
** Meets national yogurt association criteria for live and active culture yogurtALL yogurts are great for you if they aren't overly sweetened and whipped and processed into a "dessert". Your personal immunity to colds and other "bugs"comes 70% from your "gut"....when your digestion is "good and happy", you are most likely feeling healthy and are free of colds and other bugs....so eat your yogurts!