The foundation of all effective weight loss programs is to eat fewer calories than you burn (regardless of whether it’s keto, low-carb, low fat, IF, paleo). But the solution to your weight loss goal is not as simple as eating as little as possible; if you eat TOO low under what your body is burning each day, not only will you be miserable from hunger and lack of energy, but you’ll also be encouraging your body to harvest muscle instead of fat to fuel itself, screw up your hormones, and oftentimes that results in your body going into survival-mode and storing anything you do give it around your middle because it doesn’t know when you’ll fuel it next. So too much of a deficit can create problems for us, hormonally and otherwise (more on this below!)
The optimal calorie deficit is large enough to stimulate steady fat loss, but not so large that you’re always hungry and lethargic. Avoiding a calorie deficit that is too large is even more important for those who exercise frequently, who need to keep their muscles well-fueled for training. The calorie deficit “sweet spot” for many active folks is generally 300 to 500 calories per day under your Total Daily Energy Expenditure (TDEE – we have another post explaining this in more detail!), but we’d advise consulting a coach for a more personalized solution to your specific situation.
In a similar vein, staying in a caloric deficit for too long isn’t ideal either. While restricting calories is a must for fat loss, it can be detrimental when done for too long. It’s best to cycle deficits with periods of maintenance throughout the year.
At a certain point, a calorie deficit can do more harm than good, so it’s important to come out of that deficit and feed your body the calories it needs to properly function. Prolonged periods of dieting will cause your body to start to burn through muscle mass, which is not what we want because muscle causes your metabolism to “run hotter” so-to-speak and helps you burn more calories throughout the day, even at rest. When you diet for extended periods, to reduce your body’s caloric expenditure, your body will increase its catabolic state to survive, so your body goes into starvation mode due to your diet. Hormonally, again, bad things occur: testosterone goes down, grehlin (what makes you feel hungry) increases, cortisol (a stress hormone) increases, leptin (what makes you feel full) drops, etc. Basically, you’ll feel hungrier, cravings get worse, your workouts and strength will suffer, your mood will go down, and your libido will likely drop as well.
Working with a coach can help you navigate through slowly and strategically bringing you back up to periods of maintenance calories before going back into another round of a deficit, or even working in deliberate refeeds, depending on your goals, plan, and training. Even if you still have weight to lose, this can ease the process and approach your fat loss in a healthier and more productive way!