You're eating too much during your eating window. “If you end up consuming the same number of calories (or more) during your eating windows as before you started intermittent fasting, then you won't lose weight.”
You're not eating enough
If you've hit a weight loss plateau after losing a few pounds, says Melanie Boehmer, R.D. of Lenox Hill Hospital in New York City, you may be eating too few calories. That's because our bodies adjust to whatever we throw at them, she says.
You're eating too much
If you're in ketosis but not losing weight, it could be that you're eating more than your body can burn. Fat has twice the number of calories per gram than protein or carbs do.
YOU'RE NOT EATING ENOUGH DURING YOUR WINDOW
You'll be so hungry, you may start eating and not stop. As well, the body stores food to protect itself. Your body will sense the need to stock up on reserves and may store those extra pounds as fat instead of lean muscle.
After the first week of intermittent fasting, you'll probably notice less bloating and a tighter, slimmer look and feel to your midsection. Some people will enjoy some weight loss by week two, but don't be discouraged if your weight scale hasn't budged. Continue for another 4-6 weeks, and you should see changes.
What Breaks a Fast? Strictly speaking: any amount of calories, no matter how small, disrupts the fasting process. If you're following your intermittent fasting plan to the letter, that means no calories, whatsoever, for the entirety of your fasting window.
You're eating too much during your eating window.
“If you end up consuming the same number of calories (or more) during your eating windows as before you started intermittent fasting, then you won't lose weight.”
"Switch up your feeding window, or you can switch to alternate days fasting," Karen told POPSUGAR. "At the very least, incorporate one non-fasting day to help reset your metabolism." Just be sure to avoid something called refeeding syndrome, in which you eat too much too quickly after fasting.
Intermittent fasting isn't an effective weight-loss technique, according to the longest and most thorough study published on the topic. The study, published Wednesday in the New England Journal of Medicine, followed 139 patients considered obese over a period of one year.
Fat burning typically begins after approximately 12 hours of fasting and escalates between 16 and 24 hours of fasting.
Research shows that alternate-day fasting trials lasting 3–12 weeks, as well as whole-day fasting trials lasting 12–24 weeks, reduce body weight and body fat ( 19 , 20 ).
Though intermittent fasting may improve weight loss, it is often due to the loss of subcutaneous fat (this also holds for liposuction) and not visceral fat loss. Recent research states that visceral fat often becomes resistant to fat breakdown during intermittent fasting.
You can't lose weight on 1200 calories a day because you're no longer in a calorie deficit. Your body has adapted to what it's been doing and plateaued. If you start your diet with a 500 calorie deficit per day, your body adapts to this in various way so that over time your energy requirements are reduced.
It simply takes time. Another common reason why people report not losing weight despite reducing their calories is that they don't give it enough time. Our bodies will do their utmost to hold on to our fat reserves and you often have to be in a calorie deficit for a while before you will see any meaningful weight loss.
May Hinder Weight Loss
Intermittent fasting is commonly associated with weight loss. However, Newgent explains that many people actually gain weight due to overeating during non-fasting times. She also points out that “any long period of fasting can ultimately slow down your metabolism.”
There is one rule for intermittent fasting: no eating or drinking calorie foods during your fasting period. That means that you can drink black coffee, water, and zero-calorie beverages are allowed during the fast, but no solid foods.
You can repeat this cycle as frequently as you'd like — from just once or twice per week to every day, depending on your preference. The popularity of this fasting method has grown widely among those looking to lose weight and burn fat.
You can pick a daily approach, which restricts daily eating to one six- to eight-hour period each day. For instance, you may choose to try 16/8 fasting: eating for eight hours and fasting for 16. Williams is a fan of the daily regimen: She says most people find it easy to stick with this pattern over the long term.
Mostly, losing weight is an internal process. You will first lose hard fat that surrounds your organs like liver, kidneys and then you will start to lose soft fat like waistline and thigh fat. The fat loss from around the organs makes you leaner and stronger.