The Biggest Mistakes People Make in a Calorie Deficit
If you’re trying to lose weight, you’ve probably heard that you need to be in a calorie deficit. And it’s true—consuming fewer calories than your body burns is the key to weight loss. But just because something is simple doesn’t mean it’s easy. Over the years, I’ve seen (and made) plenty of mistakes when it comes to a calorie deficit. Let’s talk about the biggest pitfalls and how to avoid them so you can actually reach your goals and maintain them long-term.
1. Cutting Out Entire Food Groups
Unless you have a food allergy or medical condition, completely eliminating food groups is usually a recipe for failure. It might seem like cutting out carbs, sugar, or going dairy-free will fast-track your results, but these extreme changes are rarely sustainable. Many people find that after restricting a certain food, they eventually give in and overeat it—undoing all their progress. A calorie deficit works no matter what foods you include, so rather than eliminating things you love, focus on moderation and balance.
2. Falling for Juice Cleanses & Crash Diets
Juicing diets and other extreme cleanses promise quick weight loss, and while they do lead to rapid drops on the scale, it’s mostly water weight and muscle loss—not sustainable fat loss. These diets are often dangerously low in calories, lack fiber and protein, and leave you feeling exhausted and hungry. Plus, your body already has a built-in detox system—your liver and kidneys! Instead of cleansing, aim for a balanced diet full of whole foods, fiber, and protein to keep your metabolism and energy levels steady.
3. Overestimating the Role of Exercise
I’ve been guilty of this one myself—spending hours at the gym, thinking I could outwork my diet. The truth is, exercise only accounts for about 5% of your daily metabolic burn. It’s great for your health, but it’s not the magic bullet for weight loss. A few common exercise-related mistakes include:
Not adjusting your diet: Many people start working out but don’t adjust their calorie intake, making it harder to see results.
Underfueling: Eating too little can backfire by making you cranky, increasing your risk for binges later in the day, giving you fatigue, and making your workouts harder and less effective.
Eating back exercise calories: Fitness watches and cardio machines can drastically overestimate calorie burn, leading people to think they can eat more than they should. Unless you exercise intensely like endurance running, bodybuilding, or play competitive sports, you most likely do not need to eat back your calories if you are trying to lose weight.
4. Ignoring NEAT (Non-Exercise Activity Thermogenesis)
One of the most underrated ways to burn more calories is increasing NEAT, which includes all the movement you do outside of structured workouts—walking, fidgeting, standing, and general daily movement. NEAT can have a bigger impact on your total calorie burn than exercise alone! Some easy ways to boost your NEAT include:
Taking regular walks throughout the day (I walk my dog Lily daily)
Parking farther away from your destination
Taking the stairs instead of the elevator
Standing up and moving every hour Focusing on small, consistent movement throughout the day is an easier and more effective way to boost calorie burn without over-relying on formal exercise.
5. Not Enjoying Your Exercise
Exercise should be something you look forward to, not something you force yourself to do just to burn calories. Instead of picking a workout solely because it’s “effective,” find activities you genuinely enjoy—whether that’s weightlifting, dancing, hiking, or yoga. Not only will this make you more consistent, but it’ll also help you build strength, reduce stress, and improve overall well-being beyond just weight loss. Exercise is just as much about longevity, mobility, and mental health as it is about burning calories—so find something that keeps you moving and makes you feel good.
6. Thinking You’re in a Deficit When You’re Not
One of the most common pitfalls I see is people thinking they’re in a calorie deficit when they actually aren’t. This often happens when:
You eat “clean” but don’t track portions: Just because something is healthy doesn’t mean it’s low in calories.
You eat consistently all week but take weekends off: If you eat in a deficit Monday through Friday but overeat on Saturday and Sunday, you might erase your progress without realizing it.
You rely on guesswork instead of tracking: If you’re not seeing progress, measuring your intake (even temporarily) can help you pinpoint where adjustments need to be made.
7. Approaching Aggressive Dieting the Wrong Way
Aggressive dieting—cutting calories significantly for a short period—can be effective, but only for the right person. It’s best suited for those who have a good relationship with food and can handle short-term hunger without spiraling into restriction and binge cycles. When done properly, hunger will initially increase but then decrease as your body adapts. However, this is not a long-term approach and should only be done for a few weeks under professional guidance. Extreme calorie cuts require careful monitoring to prevent muscle loss, nutrient deficiencies, and metabolic slowdown.
The Bottom Line
A calorie deficit works, but it’s easy to go about it the wrong way. Instead of extreme restrictions, over-exercising, or relying on misleading fitness data, focus on a balanced approach. Eat all food groups in moderation, avoid crash diets, be mindful of how you fuel your body, and keep moving in ways that feel good. Sustainable weight loss isn’t about suffering—it’s about building habits you can maintain for life.
If you’re struggling with your nutrition or want a plan tailored to your lifestyle, I can help! As a nutrition coach, I work with clients to create sustainable, effective strategies for weight loss and overall health.
