Updated 14-Sep-2023
Canola oil is made from the canola plant, a genetically modified rapeseed plant. This was done back in the 1970s through cross-breeding to remove glucosinates and erucic acid, as those can be inedible and/or toxic. Canola is an invented word combining Canada and oil/ola).
Canola is seen as a healthy oil for cooking as it is low in saturated fat and high in unsaturated fat. In many cases it is compared with olive oil, with the added advantage of lower cost. However, animal studies have indicated that exposure to canola oil increases body weight and impairments in working memory. This militates against the trend to recommend it over olive oil.
That said, canola oil is better than (less worse than) other edible oils (aside from olive oil) at increasing cardiometabolic risk factors. What can best be said is edible oils should be consumed in small amounts, and canola oil is less harmful than other edible oils, aside from olive oil.
Canola does have trans-fats of 1.9-3.6% due to the process of refining, compared with 0.5% for olive oil. It is important to avoid overheating or burning all oils as that increases the trans-fats and degrades the omega-3 and other nutrients. High temperature deep frying for extended periods has the dame degrading effect.
Overall, if one must use an oil other than olive oil (due to cooking at a higher temperature or a need for a more neutral flavor), then let it be canola oil. That said, there is quite damning evidence for the significant harm of vegetable oils in general.