You don’t want to make this an excuse for overfeeding and under-exercising your cat, but some feline friends are going to be putting on weight because of polymorphism of the feline MC4R gene. Although, it is generally agreed that the normal reason for weight gain in domestic cats is under activity and overfeeding. This might include eating for pleasure because they are bored or they get into a habit of eating at certain times even though they are not hungry.
We know that humans, rats and dogs, and I presume other animals, can be genetically predisposed to obesity. As at December 7, 2021, as I understand it, polymorphism in the feline MC4R gene has been found to be associated with obesity. “Polymorphism” means something occurring in different forms. In this instance it must mean that this gene can be in different forms because it can be mutated which affects how it works (see below).
You won’t know whether your cat carries this mutated gene causing weight gain although you may have a hunch that they are because you feed them well with the right quality and quantity of cat food and they still put on weight.
Low carb, high protein diet
The experts will probably say that a high-carbohydrate cat diet can lead to the highest insulin blood concentrations and therefore it might be useful to avoid high-carbohydrate diets in cats predisposed to being overweight.
In other words, if you suspect that your cat might be genetically predisposed to putting on weight you should avoid a dry food diet because they are high in carbohydrates. You probably know that dry cat diets are high in carbohydrates because the manufacturing process demands that this is the case. You can’t make kibble pellets without the presence of carbohydrates, as I understand it.
MC4R and diabetes
And a study has also found that the MC4R gene may be implicated in Type II diabetes. I don’t know whether the gene is separately linked to type II diabetes or whether it is indirectly linked to type II diabetes through obesity.
Maintains stable body weight
Incidentally, mutations of the MC4R gene are associated with childhood-onset obesity. The long description of MC4R is ‘melanocortin-4-receptor gene’. It is a key regulator of energy homeostasis, food intake and body weight. “Homeostasis” means “tending towards a stable equilibrium”. I take this to mean that this gene helps to maintain a stable bodyweight and if it is mutated and can no longer do that which can lead to weight gain and obesity.
Postscript: high protein feline diets are useful in what is called glycaemic control which means controlling blood sugar levels.
Studies referred to in preparing this page:
- Metabolic response to three different diets in lean cats and cats predisposed to overweight
- A genome-wide association study identifies novel candidate genes for susceptibility to diabetes mellitus in non-obese cats
- A novel MC4R mutation associated with childhood-onset obesity: A case report