Second, weight is a weird thing that can go up or down for a dozen different reasons, many of which have nothing to do with fat or muscle being lost or gained. This is part of why I recommend weighing yourself daily and only paying attention to the weekly average (full detail here), not adjusting your calories based on what you see after 1 week (I suggest waiting 2-3 weeks before making changes to confirm that changes actually need to be made), and tracking your progress using more than just your weight on the scale (body fat percentage, measurements, pictures, mirror).
I myself try to eat balanced meal because for the most part I understand that protein, carbs, and even fat have essential benefits to the body that have nothing to do with losing weight. Do you agree? Plus, I like to eat throughout the day, if you just ate crap then you would hit your daily limit faster and have to stop eating to stay in your deficit.
Your parents weren’t kidding about how important veggies are for a healthy body. What they probably didn’t tell you, however, was that snacking on veggies is also one of the easiest ways to shed unwanted belly fat, too. According to a study published in the Journal of the Academy of Nutrition and Dietetics, opting for non-starchy veggies, like cauliflower, broccoli, and cucumber, as snacks helped overweight kids shed 17 percent of their visceral fat while improving their insulin sensitivity over a five-year period. Think snacking on veggies will leave you hungry? The 20 Most Filling Fruits and Veggies will have your belly satisfied in no time.
Make sure that the diet has been studied extensively for safety — and discuss any changes with your physician or registered dietitian before beginning a new diet. (If you don’t have a dietitian, find one in your area at the Academy of Nutrition and Dietetics website.) And do a self-check to ensure the diet fits with your own values and preferences.
To start off, aim to do ab work 3 or 4 times a week on non-consecutive days with at least 24 hours of rest in between sessions, says Gagliardi. During those sessions, you can start with simpler moves like crunches, bicycle crunches, and planks. Even though you may only be directly targeting your abs 3 or 4 times a week, you should still be activating your core (aka, tightening your ab muscles) in every workout you do, says Gagliardi.
Simply take a good hard look at your diet, make a few modifications you can stick with and get your body moving. Not sure where you stand on diet? Write down everything you eat this week, then compare it to the list above and see where you could have made better choices. Don’t beat yourself up though, learning how to lose stomach fat fast is a process. Simply find areas to improve and work on them next week.