If you've never dieted before, or tried and failed, start with the basics to ease into a lifelong change. Your body, taste buds, and lifestyle need time to adapt so no matter how gung-ho you are, I suggest taking dieting in stages. Aim to lose ~1% of your bodyweight each week. If you lose too little, you'll never see the results and get discouraged. If you lose too much, you'll feel weak, lose muscle, might wreck your metabolism, and could encounter health issues.
Easy Fixes
If you're overweight due to overeating and eating badly, you can make good initial losses by cutting out obvious offenders like extra helpings, dessert, and eating out. Changing to sugar-free beverages and cutting out candy snacking are also easy targets for someone who has never dieted. Diet sodas may taste weird at first, but after a couple weeks, you won't remember the difference. These easy fixes will work for a while, but eventually, you will plateau (stop losing weight) and need other strategies.
Food Log
Most people don't realize how much they eat or how badly until they begin writing it down. Keeping a food log keeps you honest with yourself, illuminates patterns, makes you question your unhealthy choices more, provides a record of accomplishment, and helps you plan better. Knowing you will have a record of bad choices, helps you make better ones prompting additional weight loss.
Count Calories
Food manufacturers use a variety of labels to indicate their product is healthy, but that doesn't mean that it's low in calorie. Even the "low calorie" label can't be trusted because they are often compared to extremely high calorie products. If you are serious about losing weight, you'll eventually need to start counting calories and adding them into your food log.
It takes time, but there are countless resources to help you: food labels, phone apps, spreadsheet programs, calorie counting websites, and many food manufacturers and chain restuarants have nutritional information on their websites. You'll get faster and more accurate over time so don't worry about being perfect when you start.
You may be tempted to try an "easy" theme or avoidance diet that doesn't require calorie counting, but it won't take you very far. Calorie counting is a skill you will use for the rest of your life and is the first skill needed for more advanced dieting. If you can't devote a few minutes of your day to log your caloric intake, then you're not serious about dieting and will likely join the large crowd of "tried and failed" dieters. Since this crowd is less likely to try dieting again, don't let yourself fall into it!
Plan Every Bite
After using a food log, you'll probably realize you could fill a lot of it out ahead of time based on what you buy at the grocery store. You've stumbled into planning, which is the conerstone of all effective dieting. Eating is relaxing and your body always wants surplus calories, lots of fat, and quick carbs so you need to plan what you're going to eat rather than letting your body decide.
First, figure out which meals will be home-cooked, prepackaged, or eaten out so you have a preview of your calorie count for the week and how much weight you can expect to lose. Don't leave it up to how you feel a certain day or you'll end up going out for burgers with coworkers more often than eating that homemade chicken salad with vinagrette.
Second, make a weekly grocery list and stick to it at the store. This is the most important tip for dieting because you can only be as healthy as your shopping cart. If you don't buy ice cream, you'll never have any at home to tempt you. It may help to tell yourself you can always buy cookies next week instead.
Third, keep healthy snacks around for those times when you have to have something more. Snacking is not a failure. Our bodies are pushing us for things all day long and sometimes, you'll give in. Accepting this and learning to work with it is more realistic than trying to be perfect for months on end. Just make sure that when you do break your plan, there is a protein bar to reach for instead of a jar of Nutella.
Last, balance your upcoming splurges. If you know you're going to a noon birthday party with pizza and cake, eat an especially low calorie breakfast and plan on grilled chicken and roasted vegetables for dinner.
