Can You Lose Weight by Not Eating?

If you came looking for confirmation that skipping meals or severely restricting calories is a good way to lose weight, you’ve come to the wrong place. The truth is, starving yourself will not help you achieve the weight loss results you’re looking for.

Why? Because it only ends in one of two ways — you develop a severe and life-threatening illness (anorexia), or you regain the weight.

They’re called crash diets for a reason — they don’t end well.

Prolonged calorie restriction typically backfires — leading you to regain the weight or even put on excess pounds. Achieving healthy weight loss requires a more holistic approach. Here’s why.

Does skipping meals help you lose weight? Yes, but not in a good way.

When you’re not eating enough, your body is forced to switch to stored nutrients for energy, which leads to weight loss.

But when your body isn’t receiving adequate fuel, it can’t thrive. You might be dropping weight, but your health isn’t improving. On the contrary, your health can take a turn.

Without adequate energy, you may quickly find yourself feeling sluggish, headachy, and tired.

Let’s look at a few popular methods for weight loss that involve varying approaches to calorie restriction.

Cutting Calories

Experts typically recommend a 500–750 calorie deficit for gradual weight loss.

This means eating 500–750 fewer calories than you burn each day, either by consuming less, exercising more, or (ideally) a combination of both.

This could be achieved by reducing portion sizes, replacing high-calorie foods with nutrient-dense, lower-calorie foods, and boosting physical activity.

Calorie reduction in the form of a deficit is not the same as not eating. It still provides your body with the energy (and nutrients) it needs while creating an environment that promotes a loss of excess body weight.

Intermittent Fasting

Intermittent fasting (aka time-restricted feeding) has become a popular way to lose weight. There are various ways to approach intermittent fasting, but generally, you divide your day into an eating window and a fasting window.

Cycling between eating and fasting helps you create a calorie deficit and encourages healthy weight loss.

Additionally, fasting periods can lead to changes in hormones related to appetite and metabolism. For instance, they can promote increased norepinephrine and human growth hormone, enhancing fat-burning and preserving muscle mass.

Some people also find that practicing intermittent fasting helps improve their awareness of hunger cues and reduces mindless eating.

Combined with a balanced diet and regular physical activity, intermittent fasting can be an effective strategy for achieving your weight loss goals, when done safely.

However, note that intermittent fasting programs don’t typically focus on the nutritional quality of the food you’re eating — only the timing of your meals. You’ll want to incorporate nutrient quality into your eating plan if you’re considering intermittent fasting.

Starving Yourself

There’s a misconception that if you just stop eating, you’ll lose weight — and then you can return to eating normally and maintain that weight. While this approach isn’t just ineffective, it’s potentially harmful to your physical and mental well-being.

Severe calorie restriction may result in initial weight loss. That’s because your body is designed to adapt to various situations in order to keep you alive.

In the case of starvation, your body responds to prolonged calorie deprivation by slowing down its metabolic rate to conserve energy.

This can ultimately hinder weight loss efforts and result in the loss of lean muscle mass rather than body fat.

Once you start eating normally again, your body is more likely to respond by holding onto those calories it’s been missing. Are we saying that not eating can make you gain weight? In the big picture, yes, it’s possible.

This is why it’s called “yo-yo dieting.” With extreme calorie fluctuations comes highly inconsistent and unsustainable weight management patterns.

Furthermore, severe calorie restriction can lead to increased hunger, mood swings, fatigue, nutrient deficiencies, and serious health complications. It’s not a fun way of life.

Occasionally not eating may seem like no big deal, but it can have serious consequences.

Metabolism Effects

When you don't eat for an extended period, your body experiences metabolic changes to adapt to the lack of incoming energy.

Initially, it will rely on glycogen (stored glucose) for fuel, which reduces blood sugar levels. In response, your pancreas secretes less insulin (the hormone that moves sugar from your blood into your cells for energy), and your body begins breaking down stored fat for energy through a process called lipolysis.

While this may seem like a win for weight loss, prolonged fasting can backfire. It eventually will slow your metabolism as your body attempts to conserve energy.

Not getting enough calories for long periods can also promote muscle loss, further reducing the amount of calories you’re burning.

Ultimately, these adaptations can make it harder to sustain weight loss, and may set you up for weight gain once you're back to regular eating.

Mental Health Consequences

Think about the last time you missed a meal. Eventually, your body tells you it needs food (again, survival mechanism).

Perhaps you started getting a headache, felt shaky from low blood sugar, experienced lightheadedness, or exhibited the irritability of being “hangry.”

Not eating can be hard on your mental health. For one, when your body isn’t receiving the fuel it needs, it can manifest as anxiousness, stress, or even depression.

Ongoing hunger and nutrient deficiencies from severe restriction can impact the function of neurotransmitters (brain chemicals), leading to mood swings and difficulty concentrating.

Plus, when you’re restricting food, said food tends to live rent-free in your thoughts. This can lead to obsessive behaviors and a disordered relationship with food and your body.

Over time, chronic food restriction can increase your risk of disordered eating habits and dangerous disorders like anorexia nervosa (extremely restrictive eating), bulimia nervosa (a pattern of restriction and overeating often followed by self-induced vomiting or laxative abuse), or binge-eating disorder (a cycle of overconsumption).

You’re more likely to overeat following a period of restriction.

Effects on Your Body

Not eating can have a profound impact on your body. At first, when faced with severe caloric restriction, your body will switch from utilizing readily available glucose to stored energy sources, like glycogen and fat, to meet its energy needs.

As these reserves become depleted, your metabolism slows to conserve energy. When this happens, you’ll probably experience fatigue, weakness, trouble concentrating, and reduced physical performance.

Ongoing starvation will disrupt your hormonal balance and production, too. Since hormones are involved in countless functions, imbalances can impact your immunity, digestion, and even your fertility and reproductive health.

As nutrient deficiencies develop, your vital organs and bodily systems will become more significantly affected.

Signs of malnutrition can include hair loss, dizziness, easily bruising, skin dryness, and finding yourself sick more often (or for longer) due to impaired immunity.

Without enough nutrients, your body can’t produce enough energy to maintain normal functions, down to the cellular level.

Finally, restriction can even affect your life expectancy. One study found that eating only one meal per day was associated with a higher risk of death from heart disease and all causes.

People who skipped breakfast had a higher risk of dying from heart disease and people who didn’t eat lunch or dinner were more likely to die in general. How’s that for the importance of regularly eating?

In addition to the many physical and mental consequences of not eating, there is also a real risk of setting yourself up for a disordered eating pattern, which can be extremely damaging and difficult to recover from.

Starvation, intentional or not, can trigger an unhealthy relationship with food, body image, and your weight.

Prolonged fasting or extreme calorie restriction can lead to obsessive thoughts about food, feelings of guilt or shame associated with eating, and a distorted perception of body image.

Put all of these things together and you have a perfect storm for developing an eating disorder. Once this type of disordered eating pattern is established, it can be really difficult to re-establish a healthy relationship with food.

It also puts you at a very high risk of malnutrition, reproductive problems, reduced bone density and an increased risk of fractures, depression, and anemia, to name a few.

The successful road to recovery from an eating disorder involves medical and mental health support, such as long-term behavioral therapy and nutritional intervention from a registered dietitian specializing in eating disorder treatment.

Not eating may seem like the fastest way to get from A to B, but in reality, it’s a huge detour from the long-term weight management and overall health you’re pursuing.

Sustainable weight loss isn't just about shedding pounds; it's about cultivating habits that nourish the body, leading to long-term health and vitality.

We encourage you to consider a multimodal lifestyle approach to your weight loss goals, starting with the weight loss strategies below.

More Nutrients

Yes, you will need to create a calorie deficit to promote weight loss. However, this doesn’t mean the fewer calories, the better. Nutrition is king whether or not your goal is weight loss.

Optimal nutrition is an essential piece of achieving and maintaining a healthy weight — as well as supporting long-term health outcomes. This means not restricting meals, but boosting your intake of nutritious foods.

So if you’ve been wondering if skipping dinner is good for weight loss, the answer is a resounding no. Providing your body with solid nutrition creates an environment in which your health journey can flourish.

Focus on maintaining a balanced diet rich in foods like fruits, vegetables, lean proteins, and whole grains. These foods promote satiety, regulate blood sugar, and enhance your energy.

Nutrient-dense foods also ensure you receive the vitamins, minerals, fiber, and antioxidants to prevent deficiencies and disease.

Hydration

You’ve heard the rule of drinking eight glasses of water a day to prevent dehydration, but did you know your fluid intake also supports healthy weight loss?

Adequate hydration supports healthy digestion and metabolism. It also promotes the breakdown of fat stores and can help curb your appetite to prevent cravings and overeating.

Our advice: Keep a reusable water bottle with you to sip throughout the day. If you get sick of plain water, try infusing it with fresh fruit or herbs, or swap in herbal teas or unsweetened seltzer waters.

Daily Movement

Your body craves movement. Increasing your physical activity is an important part of weight loss. Exercise boosts metabolism, promotes lean muscle mass, burns more calories, and improves overall fitness.

Plus, it helps reduce stress and improve mood, which can help prevent emotional eating and support weight management goals.

Experts say we should aim for a minimum of 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity aerobic exercise per week for basic health and disease prevention.

Reach for 225-420 minutes per week for weight loss, and include strength training at least twice per week.

Rotate a variety of activities you enjoy, like swimming, playing tennis, dancing, joining a group fitness class, biking, yoga, or martial arts.

Weight Loss Medications

In some cases, healthy lifestyle changes aren’t enough to achieve weight loss goals with obesity. When this happens, many people find it helpful to add weight loss medications under the supervision of a medical provider. These medications include:

• Glucagon-like peptide-1 receptor agonists: Better known as GLP-1s, these work either by suppressing appetite, reducing nutrient absorption, or increasing metabolism. GLP-1s include Ozempic®, Mounjaro®, and compounded semaglutide.

• Contrave®: This is a combination of an antidepressant (bupropion) and a medication used to treat alcohol and opioid dependence (naltrexone). They work together to target the brain’s reward centers for weight loss.

• Metformin: Originally made for managing type 2 diabetes, this drug may also support weight loss by improving insulin sensitivity and promoting fullness.

• Topiramate: This is an anti-seizure medication but can also help promote weight loss by reducing appetite and altering how things taste.

The bottom line? Not eating in an attempt to lose weight simply isn’t worth the hassle (or the risk).

While severe calorie restriction will likely trigger some short-term weight loss, your body is designed to adapt to keep you alive and healthy — which means starvation isn’t going to get you the results you’re seeking.

• Not eating is dangerous. Your body needs food, period. There are far more risks than health benefits of not eating. Plus, not eating doesn’t equate to losing weight fast. It eventually backfires, making it harder to achieve and sustain a healthy weight.

• Healthy weight loss is a long game. No quick-fix will provide the long-term results you want. A combination of nutrition, movement, and hydration are key. Making the best choices you can each day build upon each other and bring you closer to your goals.

• Seek personalized support. Weight loss is a personal journey and there’s no one-size-fits-all approach. Consult with professionals like a registered dietitian for nutrition advice, a personal trainer for a fitness plan, and a medical provider regarding other options, like weight loss medications.

Need guidance? We’re here to help! Get connected to a Hers licensed healthcare provider by taking our free online weight loss assessment.