For a companion dog, the most important environmental factor is the owner, who is responsible for providing everything that is necessary for the health and welfare of the dog. Still, one of the most often compromised measures of an average companion dog is its body condition, with overweight and obese animals representing a growing welfare problem around the world. Using an extensive online survey that was distributed among Hungarian dog owners, we wanted to know whether those obesogenic factors that were identified mostly in high-GDP countries’ pet dog populations would hold their relevance in a much lower average income country as well. We found several associations between the body condition of canine companions and various demographics, environmental and behavioral factors. Older dogs reportedly had an accelerating propensity for being overweight. Joint activity and performing dog sports both reduced the likelihood of being an overweight dog. Main food types also had significant associations with the body condition of dogs—meanwhile, the feeding of commercial dog food (kibble) and/or leftovers of human meals coincided with being overweight, dogs that were fed (fully, or at least partly) with raw food were less likely overweight. In the case of owner-reported behavioral problems, the food-related issues (stealing food, overeating, etc.) were clustered to a dimension together with problem behaviors such as excessive barking and overt aggression. Beyond showing a good agreement with earlier surveys on associated factors with canine obesity, our study revealed some interesting new details that could be used in the prevention of overweight problems in dogs.