Intermittent fasting (IF) has become a prominent trend in the realm of weight loss, embraced by various celebrities such as Halle Berry, Jenna Jameson, Jennifer Garner, Stassi Schroeder, and Vanessa Hudgens. Beyond its association with weight loss, limited research suggests that intermittent fasting may offer additional benefits, including cholesterol reduction, improved concentration, and enhanced sleep quality.
However, the effectiveness of IF for weight loss hinges on correct implementation, and there are common mistakes that individuals might make, inadvertently hindering their progress. Achieving the desired results involves careful attention to the timing of fasting and the choices made during eating windows. If you find that your weight loss isn’t progressing despite practicing intermittent fasting, read on to discover the major mistakes associated with IF diets, as highlighted by registered dietitians, and learn how to address each issue.
So how does IF work for weight loss, exactly?
“Intermittent fasting is centered around when you eat,” explains Charlotte Martin, MS, RDN, CPT, owner of Shaped by Charlotte, LLC. “Depending on the IF approach, you’re either shortening the eating window each day or engaging in about 24-hour fasts one or more times a week.” A popular method is the 16:8 approach, where fasting occurs for a 16-hour window, such as from 8 p.m. to 12 p.m. the next day.
By confining your food consumption to a condensed time frame, you naturally reduce your caloric intake, potentially leading to weight loss. (It’s important to note that weight loss fundamentally occurs when you consume fewer calories than you expend each day.) Martin adds, “Not only are you taking in fewer calories, but you’re also slowing down your insulin pump, which may boost fat burn.”
How long does it take to start losing weight when you’re doing intermittent fasting?
There are a lot of factors that can contribute to how long it may take for the weight to start coming off. “Rate of weight loss will vary greatly from person to person depending on several factors, including: starting weight, the intermittent fasting approach used, the types of (and how much) food consumed during the eating windows, and more,” says Martin.
If you end up reducing your overall caloric intake right away and you consistently eat fewer calories than you expend, then you should start losing weight immediately. “However, you likely won’t notice any weight loss results for at least a couple of weeks,” notes Martin, adding that some weight loss in the beginning will “likely be water weight.”
“Depending on the calorie amount you consume while practicing intermittent fasting, you could experience an approximate one- to two-pound weight loss per week. This would mean it could take upwards of eight to 10 weeks to notice significant weight loss,” says Kristen Smith, MS, RD, spokesperson for the Academy of Nutrition and Dietetics.
However, if you’re losing more than that, it could be a red flag. Smith advises, “If you notice yourself losing a noticeable amount of weight during the first few weeks of following an intermittent fasting plan, you should likely re-evaluate your calorie intake to ensure you are consuming adequate nutrition to meet your body’s needs.”
So if I’m *not* losing weight with IF, what’s the problem?
- Overeating during your eating window: Consuming too many calories during your eating window can hinder weight loss. Weight loss is fundamentally about the balance between calories in and calories out. If you end up eating the same amount or even more calories during your eating window compared to before intermittent fasting, you may not experience the desired weight loss.
How to fix it: Consider using a calorie-counting app to track your intake. While not always recommended, tracking your calories for a few days with an app can provide insight into your daily calorie consumption. These apps often estimate the approximate daily calorie amount needed for weight loss, serving as a useful starting point. By identifying meals or foods with unexpectedly high calorie content, you can make necessary adjustments to your diet.
- Insufficient calorie intake on non-fasting days: Inadequate calorie consumption on days when you’re not fasting can lead your body to conserve energy instead of burning it, according to Smith.
How to fix it: Develop a meal plan for non-fasting days to ensure you’re getting enough calories. Smith suggests creating a balanced meal plan with at least 300 to 500 calories per meal. This approach eliminates guesswork and helps guarantee that you meet your calorie needs on non-fasting days.
- Consuming less-nutritious foods: While intermittent fasting emphasizes when you eat rather than what you eat, the quality of your food choices still matters for weight loss, cautions Martin. Relying on calorically dense, low-nutrient foods, such as fast food, can impede your weight loss goals.
How to fix it: Opt for nutrient-dense foods during your eating windows. Prioritize a balanced diet that includes a variety of fruits, vegetables, lean proteins, and whole grains to support your overall health and weight loss efforts.
- Insufficient fasting duration: Merely shortening your eating window by an hour each day might not yield significant weight loss results, warns Martin. This minimal adjustment may not bring about the necessary changes from your regular eating routine.
How to address it: Martin recommends aiming for a 10-hour eating window, which corresponds to a 14-hour fasting period. Starting with a longer eating window and gradually reducing it can be a practical approach, especially if your usual eating window is considerably longer. Experimenting with different fasting durations allows you to find a balance that works best for your lifestyle and weight loss goals.
- Skipping meals during your eating window: Skipping meals or not consuming enough during your eating window can lead to extreme hunger during fasting periods, increasing the likelihood of breaking your fast prematurely. This restriction may also result in overeating or bingeing during the next eating window, leading to an overall increase in calorie intake.
How to fix it: Ensure you eat until you’re comfortably full but not overstuffed during your eating windows, advises Martin. Additionally, consider meal prepping on weekends to avoid skipping meals when busy or deviating from your schedule.
- Choosing the wrong type of fasting plan: Not all intermittent fasting plans may align with your lifestyle or support your specific metabolic needs. Selecting a plan that doesn’t suit your exercise routine or daily activities can hinder your adherence to intermittent fasting.
How to fix it: Consult with a registered dietitian to help you choose an intermittent fasting plan that aligns with your lifestyle and dietary requirements. Tailoring the plan to your needs increases the likelihood of long-term success.
- Inadequate sleep: Insufficient sleep can impact weight loss outcomes, even though few studies directly correlate it with intermittent fasting. Prioritize getting at least 7 hours of sleep per night to support overall health and positive weight loss results.
How to fix it: As cliché as it sounds, prioritize getting a minimum of 7 hours of sleep each night, advises Smith. While challenging, make a concerted effort to achieve this goal for better overall well-being and improved outcomes in your intermittent fasting journey.
- Excessive exercise: Introducing a new exercise plan simultaneously with an intermittent fasting regimen, especially if it’s intense, can lead to decreased energy levels and increased hunger. This may result in consuming more calories during eating windows than burned through exercise.
How to fix it: Adjust your exercise intensity, especially on fasting days, to avoid energy depletion and excessive hunger. Ensure your workout routine is challenging yet manageable and enjoyable.
- Dehydration: Inadequate water intake during fasting periods can lead to dehydration and hinder the hunger-suppressing benefits of water.
How to fix it: Stay hydrated by drinking water, hot tea, black coffee, seltzer water, or tea/coffee with Stevia during fasting periods. Adequate hydration supports overall well-being and helps control hunger.
- Deviating from the plan: Consistently deviating from your intermittent fasting plan may compromise its effectiveness. Cheating or cutting corners regularly may impede the desired weight-loss benefits.
How to fix it: Choose an intermittent fasting plan that aligns with your lifestyle and can be sustained over longer periods. Committing to the plan and avoiding frequent deviations enhances its effectiveness.
- Lack of planning: Planning ahead is crucial for maintaining a healthy intermittent fasting routine. Failing to plan meals and snacks in advance can lead to impulsive and potentially unhealthy food choices.
How to fix it: Plan your meals and snacks at least a day in advance. Preparing meals, packing snacks, or reviewing restaurant menus ahead of time helps you make mindful and nutritious choices, supporting your intermittent fasting goals.
- Feeling guilty about breaking a fast: Breaking a fast earlier than planned is a common experience in intermittent fasting. Feeling guilty or ashamed about it can hinder your progress.
How to fix it: Practice self-compassion and move on. Acknowledge that intermittent fasting involves trial and error, and occasional deviations are normal. Avoid dwelling on guilt and refocus on adhering to your fasting schedule moving forward.