Stay away from High Fructose Corn Syrup and sugar in general. That is the easiest most effective way to lose weight. I know for some that is like asking you to quit smoking or drinking. I know it's hard. I quit smoking a few years back so I'm familiar with addictions. I also know a lot of people don't see the comparison of sugar to an addictive substance. After all a person has to eat to live, right. But that's exactly the point, living. Sugar and especially man made high fructose corn syrup is killing Americans. A recent study suggested a person doesn't even have to be obese to suffer great health consequences. Just some extra fat around the belly could be a great warning sign.
The bad thing about sugar in general is the fructose. Fructose is thought to fail in signaling the body it's full, causing over eating. It spikes your insulin, which ultimately makes you fatter, and speeds up your aging process, like putting your foot to floor of your car's accelerator. To rephrase a classic line from Arnold Schwarzenegger, "Get rid of the sugar if you want to live". It's just that simple.
Again you say, I have to eat. Right, well that's true, so lets replace those deadly things on your menu with some healthier choices. Instead of coke, drink unsweetened tea, or even water. You do know that water is essential for life right? Coke is not, nor is Cocoa-Colas new sugar water deceptively called Vitamin Water. You have to change your way of thinking. You do not need sugar every time you eat or drink to live. If you absolutely need a sweet taste, then try a little stevia. It's natural, and you can use to wean yourself off of sugar with it. Also there are a ton of herbal teas to try for different flavors. My favorite is cherry tea. It might take you a bit to change your tastes, but taste can be trained to enjoy whatever you decide.
The only sugar you should be getting in your diet should be from fruits. The body can deal with the sugar in fruits and vegetables much easier than man made high fructose corn syrup found in cokes and most processed foods these days. Even so watch how much fruit you eat. Try to stick with vegetables and lean meat as much as possible. As a former junk food addict, I have grown amazed at how many healthy choices there really are that I enjoy eating. I grew up thinking if it wasn't coke, ice cream, hot dogs, fried chicken, and hamburgers it must taste terrible, but there really are a multitude of items I have even yet to try.
Don't be afraid of all fats. You need some fat in your diet, and of course again no processed foods. Eat one avocado a day. Grab a handful of walnuts here and there throughout the day. Personally, and I might be weird, but I like to mix a boiled egg with my avocado. That way I get the healthy fat and all the protein and other healthy nutrients from the egg in one easy to fix meal. Boil several eggs at a time and have them handy. They make great snacks throughout the day. Salmon, chicken, turkey, all make great lunches and dinners along with your choice of healthy veggies like say, broccoli, brussel sprouts, lentils, beans, cauliflower, kale, spinach, etc, etc. The first week eat as much as you want. You'll start to feel fuller, and it will be easier to cut back to normal sized portions. I guarantee you'll lose weight over a month's time that will not come back unless you start binging on sugar again.
One more piece of advice. Move. Just move around a bit. I won't lie to you, hardcore exercise is likely to get a person thinner quicker, but everyone has to start somewhere. In the long haul if all you do is walk around the park a few times a week, you'll be much healthier and burn off a few calories every week. Wash your car, clean the house, do anything, but don't sit down for more than two hours at a time. You get plenty of being still when you sleep at night. If you move around all day at work, great, now let's add twenty minutes of exercise to your daily routine.
Remember one little bit of wisdom I've learned about bad things in general. If you don't buy them, you can't eat, drink, or smoke them. Don't play around with fire, or you are going to get burned. I'm not saying you can't ever have a coke or cake on a special occasion, but just remember this. If you buy a whole case of cokes, or a whole box of cakes you are not likely to spread it out over a month's time. Instead you'll wind up eating or drinking the whole thing in a week. The only way to beat temptation is to put it away from you. It's a biblical principle, but it works as well with food just as well as sin. So try it and see how much weight you lose. In a month you'll have more energy and strength, and you'll look a whole lot better.