The key to losing weight is to have a negative energy balance. This entails that you should intake less calories than you expend. Increasing your overall daily physical activity will help immensely and this is accomplished by reducing the amount of time you spend being inactive. What many trainers neglect to tell their clients is that physical activity is only one component that will help reduce the amount time spent in an inactive state. Walking or standing instead of sitting for extended periods of time will help immensely over the long run as you are prohibiting yourself from being sedentary. House chores such as vacuuming or gardening can also contribute to the negative energy balance. (Every fifteen minutes or so try to walk or stand in your house or wherever you may be and try to take the stairs more often) Remember every form of physical activity helps immensely. Individuals in cardiac rehab frequently walk or perform simple range of motion activities so the notion that physical activity has to be a vigorous in nature is not true.
Nutrition is also key as it plays a role in maintaining a negative energy balance. Eating fruits and vegetables throughout the day and eliminating any form of binge eating that may be present in your daily routine is crucial. Eating a thorough breakfast and not skipping meals is a good starting point. You can snack on fruits throughout the day as they are very nutritious and healthy. I am sure a Nutritionist can help you with this area more so than a personal trainer.
MOST importantly do not hire a stupid trainer!!!