Some of the worst offenders are brands that you are well aware of; they are seen stacked in local supermarkets and pet supply stores, and many air lots of commercials. Pet parents see a recognizable name and assume that since it must be popular, it must be a good food. But, this is one mistake you'll want to avoid.
1-star foods (absolutely horrible):
Alpo, Gravy Train, Kibbles 'n Bits, Pedigree, Old Glory, Old Yeller, and some varieties Purina Dog Chow.
2-star foods (terrible):
Beneful, some varieties of Blue Buffalo, Cesar (Classic, Savory Delights, Sunrise, and Filet), Evolution, some varieties of Hill's Science Diet, some varieties of Iams, Mighty Dog (wet), some varieties of Purina Dog Chow, Rachael Ray Nutrish, Royal Canin, Seminole,Trader Joe's Kibble.
3-star foods (are 'okay', but your Chihuahua deserves better):
Back to Basics, some varieties of Blue Buffalo, Candae, Diamond, Eukanuba, Halo Vigor, Hill's Ideal, some varieties of Hill's Science Diet, some varieties of Iams, Natural Balance, Nature's Recipe, Newman's Own Dog Food, Nutro, many varieites of Purina, some varities of Rachael Ray, some varieties of Royal Canin, some varieties of Trader Joe's, Tuscan Natural.