Hardly. Tell that to the 1/3rd Americans who are overweight. If you know the secret to easy weight loss, please don't hold out.
It mostly comes down the the food we eat. Added sugars have made their way into nearly everything you can buy at a grocery store. Buying food that doesn't include added sugars is tricky because nearly everything has added sugar. The evidence that added sugars (especially high fructose corn syrup) are mostly to blame for the obesity epidemic, is becoming overwhelming. Significantly changing what you eat is not easy for everyone.
The biggest change needs to come as regulation to the food industry to discourage adding excessive amounts of sugars to foods. Also, stop subsidizing corn and the production of high fructose corn syrup. Obesity is a systemic problem that needs a systemic solution.