After somewhere between three and five hours, your body stops processing its last meal. There's nothing left to absorb, so insulin levels naturally decrease. Then, somewhere between eight and 12 hours after that last meal, your body starts burning stored fat. (Why don't you start burning fat sooner? Biology is sometimes a pain in the ass; it's like our bodies will do anything to hang on to fat.)
Jim said people can healthily lose half a pound to two pounds a week. In a month, that could add up to four to eight pounds lost. Since one pound of fat equals 3,500 calories, to lose one pound a week, you would have to burn approximately 500 extra calories a day. This can be achieved through eating in a healthy calorie deficit or working out to burn extra calories (or a combination of both). Other lifestyle factors also play a role. Getting enough sleep will ensure your body recovers well and that you'll be energized for your workouts the next day. And too much stress increases the stress hormone cortisol, which can increase your cravings for caloric refined carbs and comfort food, which will prevent you from losing weight (especially in your belly). Make sure, in addition to eating in a calorie deficit, that you're also getting at least seven hours of sleep a night and managing your stress.
The key to losing belly fat with exercise, though, is making sure your sweat session is intense. You’ll want to be working at 85% of your max heart rate at least, says Olson. “The higher your heart rate, the higher the release of epinephrine into the bloodstream and cells,” she explains. “A positive side effect of epinephrine is that it also activates greater release of abdominal fat into the bloodstream to be used for energy.”
6. Eat a little less. When your body gets smaller, it requires fewer calories to function properly. A 165-pound woman who works out three to five times a week may require 2,300 calories per day to maintain her weight, but the same woman at 125 pounds may only need 2,000 calories for maintenance. Trying to lose additional pounds in your lighter body means cutting back a little more. You do not need to make radical changes, however; if you’re already increasing the intensity of your workouts and eating a clean, whole-foods diet, you could probably see the scale move with a modest 100-calorie reduction per day.
High blood sugar levels coupled with high blood ketones, on the other hand, will mean that you have a pathologically low level of insulin – something non-diabetics do not suffer from. This can lead to ketoacidosis – a potentially life-threatening condition. If this happens, you’ll need to inject more insulin; if you’re at all unsure of what to do, contact a medical professional. Coveting really high blood ketones for weight control is not worth the risk for type 1 diabetics.
7. Zigzag your calories. Cycling your calories, also known as zigzagging, is the process of eating more on certain days and less on others. If you always eat 1,800 calories, try eating 1,500 calories one day and 2,000 the next. As long as you create a weekly deficit, you should see the pounds drop. Much like shocking your muscles into working harder by introducing new exercises, it’s possible to shock your metabolism by zigzagging your calories.
Dr. Smith applies this same idea to diet. He maintains that if you eat the same foods all the time, your body adjusts to that specific diet. Your metabolism stabilizes and fat accumulates as a result. By varying the types and quantities of food you eat, you’ll prevent your metabolism from slowing down and trick your body into burning more calories. In this way, diet confusion keeps your metabolism off-kilter and fuels your fat-burning engines.
"When we’re lacking in sleep, our body’s hormones get thrown off balance which can impact our hunger levels the next day. We all have two hormones that affect our appetite: ghrelin and leptin. When we don’t get enough sleep, our ghrelin levels (the hormone that makes us feel hungry) rise, and our leptin levels (the hormone that makes us feel full) drop. This means that when we’re awake, we tend to eat more but feel less satisfied. Try going to bed a little earlier than usual to avoid this imbalance and remember to remove any distractions that might prevent you from nodding off."