Are waist trainers safe? Plus exercise and dieting advice

I keep seeing these videos of these waist trainers that women are wearing that apparently in a few weeks time has helped them lose excessive amounts of weight at their hips and stomach. Im not really sure how they work or what they do but if they are safe and actually work Im considering getting one. With my work schedule the way it is and with my bills I don't have time to go to a gym or afford a membership. I also don't eat the way I should, usually skipping breakfast or I eat a bowl of captain crunch and sometimes I eat one meal a day either lunch or dinner. Im also drinking 3 or 4 cans of soda a day. I probably eat fast food once or twice a week. When I make dinner I tend to make a meat (hamburger, steak) and instant mashed potatoes or a knorrs pasta side. I rarely eat fruits or vegetables. In the past month I've gained 8 pounds. I feel like if I had a guide to follow or a simple exercise and diet plan it might help with loosing the weight. Any advice would be good advice and very much appreciated.