Exactly What Happens to Your Body When You Skip a Meal, According to Dietitians

We know what it’s like to get into the zone at the office: You have your headphones on, fingers furiously typing, and you're completely engrossed in answering and sending emails. Sometimes a busy schedule can cause you to forget the last time you had a snack, let alone a meal. That said, some people skip meals in the form of intermittent fasting, a way of dieting in which you can eat whatever you want, but only during a specific time period.

“Skipping meals, the proper way, also called intermittent fasting, can have incredible health benefits, like weight loss,” explains Brooke Alpert, RD, and author of The Diet Detox. But skipping a meal and intermittent fasting are two very different things. Skipping meals to deprive or punish yourself—or because you're too busy to eat—is different from fasting to get cravings under control and practice mindful eating. In general, forgoing eating has negative consequences for your body.

Here, experts explain exactly what happens to your body when you don’t eat enough, and offer advice on what you can do to stay fully fueled throughout the day.

You'll feel tired and sluggish.

Skipping meals and not consuming enough food during the day can literally make your head spin. You might start to feel dizzy, have low energy, and even feel like you might pass out. “This is due to the drop in blood glucose,” says Frances Largeman-Roth, RDN, a nutrition and wellness expert and author of Eating in Color. “When we don’t feed our brains, this can signal to the body that it’s time to shut things down.” This is why if you're going to practice intermittent fasting, you have to make sure you’re doing it properly—on a set schedule—and when you do eat, you’re filling up on foods that will sustain you throughout the fasting periods.

You might overeat at your next meal.

"When people skip meals, they feel like they're owed something later in the day so they tend to overeat at their next meal," explains Bonnie Taub-Dix, RDN, creator of BetterThanDieting.com, and author of Read It Before You Eat It. "But if you split up your meals throughout the course of the day, your body is able to use those nutrients more efficiently," she adds.

Taub-Dix likes to think of our bodies like a food processor: If you gradually add food into it, it will work well and do its job, but if you shove tons of food into it at once—say, after you've skipped a meal and are ravenous—then it won't work as efficiently.

To help your body function properly, be sure to enjoy three balanced meals a day—and grab a healthy snack when you’re hungry between meals. If you start to hear a little rumble in your belly, that's a sure sign it’s time to eat. Taub-Dix says the most important thing is to eat based on your internal feelings and not the clock, so when you're starting to feel like you can't concentrate, start chewing something nutritious ASAP.

You won't be in the best mood.

Your blood sugar drops when you skip meals consistently. This can greatly affect your disposition. If you’ve ever been “hangry,” then you know the feeling. “Glucose is the number one fuel for our brains so when we don’t have it, it can put us in a very bad mood,” Largeman-Roth says. That’s why if you’re skipping meals and end up feeling hangry, don't grab the first snack you find, unless it’s healthy. When people have very low blood sugar, they tend to go for very fatty or sugary foods because their body starts to crave it.

You're not able to maintain weight loss in the long run.

If you think skipping a meal is a smart way to maintain weight loss, think again. Sure, you'll naturally consume fewer calories, but there’s a good chance you’ll cave into your cravings and binge on unhealthy foods, which can lead to a dangerous cycle of yo-yo dieting. Yo-yo dieting can mess with your resting metabolism, which is the way your body burns calories in order to function. Because your meal times are so unpredictable, your body will keep what it can and won't burn calories efficiently. Your hunger hormones can also take a hit if you’re skipping meals. Your body might produce less leptin—the hunger hormone that decreases appetite—making it harder for you to discern when you're already full.

Bottom line: Skipping meals is bad for your health.

Sure, skipping meals can happen from time to time, but doing it consistently can negatively impact your health and lead to nutritional deficiencies. You’re also not able to perform at your best because all you can focus on is food. If you have trouble making time for meals because you have a busy schedule, consider these tips:

• Get into the habit of meal planning but start small. You don’t have to prep an entire week’s worth of meals at once. Instead, prepare a nutritious breakfast the night before so you have something ready to eat the next morning. If you’re cooking a big batch of soup for dinner, pack a bowl for lunch.
•  Keep healthy snacks at the ready. We all know how busy life gets, and there will be days when you’re rushing from one meeting to next without much time to eat in between. That’s where having nutrient-rich noshes at your desk can come in handy. Some good snack ideas are a handful of roasted almonds, low-sugar protein bars, and low-fat, plain Greek yogurt with fresh fruit.
• Pair a meal replacement shake with a healthy snack. If you’re really in a pinch, consuming a healthy meal replacement shake with some healthy snacks can help you get a complete meal on the go. Note that many meal replacement shakes are high in sugar and don’t have enough filling protein or fiber, so in order to make it a true meal, pair it with a healthy snack, whether it’s a banana with some natural peanut butter or celery sticks with hummus. Aim to consume between 325 to 400 calories, 15 to 25 grams of protein, five grams of fiber, and 10 to 13 grams of healthy unsaturated fat at each meal. Just remember, meal replacement shakes shouldn't turn into a regular habit. Making time to sit down and enjoy a meal should be your priority, whether you have a busy schedule or not. Stepping away from your desk to eat can do wonders for stress relief and help you feel more focused too.