Overnight Diet Guide: Does Weight Loss Happen Overnight?

Our nutrition coach analyzes Dr. Caroline Apovian, MD's approach to weight loss.

The Overnight diet may sound like a panacea: a magical rapid weight loss one-day diet that will get you to your ideal body weight.

However, the name is a bit of a misnomer because it is a low-calorie weight-loss diet that is not intended to be followed for just one day.

Rather, the term “overnight“ in the Overnight diet refers to the theory behind this weight loss diet: getting enough quality sleep every night is necessary to lose weight.

So, how do you follow the Overnight diet for weight loss or weight management? Is the Overnight diet effective? Is it safe?

This diet guide will discuss the Overnight diet plan, its principles, foods to eat and avoid, and potential Overnight diet benefits and drawbacks.

Let’s jump in!

A person sleeping.

What Is the Overnight Diet?

The Overnight diet was created by Dr. Caroline Apovian, MD, who is not only a physician but also a professor of medicine and obesity researcher at Boston University.

She published a book on the Overnight Diet plan, The Overnight Diet: The Proven Plan for Fast, Permanent Weight Loss, which is available on Amazon. 

The Overnight Diet was developed based on Dr. Apovian’s research and clinical experience working with patients who were overweight, noting not only the importance of the particular foods eaten and being in a caloric deficit but also the importance of getting a good night’s sleep for regulating hormones related to appetite and satiety.1Broussard, J. L., Kilkus, J. M., Delebecque, F., Abraham, V., Day, A., Whitmore, H. R., & Tasali, E. (2015). Elevated ghrelin predicts food intake during experimental sleep restriction. Obesity24(1), 132–138. https://doi.org/10.1002/oby.21321

‌In addition to promoting sleep, the overnight weight loss diet is much like any relatively sound diet for weight loss; it is a low-calorie diet focusing on whole, natural foods.

It is a high-protein diet that eliminates processed foods, added sugars, and refined carbohydrates.

There is also a “fasting day“ in the Overnight diet plan every week in which you only consume smoothies to provide your nutrition and calories.

A person making a smoothie.

The fasting day is termed the “Overnight Diet Power Up Day,” while the other six days of the week are termed “Overnight Diet Fuel Up Days.”

While you do not need to count calories on the Overnight diet meal plan, you do need to calculate your daily grams of protein requirement and then keep track of your protein intake.

Therefore, this high protein weight loss diet involves some amount of daily math and tracking, but if you generally follow the same Overnight diet recipes for your meals and snacks, you can get into a rhythm where you won’t need to log all your meals.

There is no set schedule for how many meals or snacks you need to eat on the Overnight diet weight loss plan per day. 

The only schedule restriction is the structure that you are supposed to follow the diet for six days and then have a one-day smoothie fast per week.

What Can You Eat On the Overnight Diet?

The Overnight Diet food list is fairly sound and not overly restrictive in terms of what you can eat, but there are limitations on the number of servings and serving sizes for certain types of foods.

A basket of fruits and vegetables.

Here is what you can eat on the Overnight diet meal plan:

Overnight Diet 6-Day FuelUp

#1: Fruits and Vegetables

You can have unlimited fruits and non-starchy vegetables on the Fuel Up Overnight diet meal plan days. 

Examples of non-starchy vegetables include leafy greens like spinach and kale, cruciferous vegetables like broccoli and cauliflower, cabbage, mushrooms, asparagus, bell peppers, onions, watercress, celery, cucumbers, zucchini, and Brussels sprouts.

#2: Lean Protein

At its core, the Overnight diet is a high-protein diet for weight loss.

Dr. Apovian suggests that you eat about twice the recommended daily allowance of protein and plenty of protein every day. 

Generally, she suggests consuming 1.5 g of protein per kilogram of body weight using your “goal weight“ rather than your current body weight. Her diet book provides a formula for how to calculate your daily protein requirement. 

The overnight diet doesn’t have many restrictions on the types of protein you eat as long as it is a lean protein source. 

Examples of lean protein include chicken breast, turkey breast, canned tuna, white fish, seafood such as scallops, lean cuts of beef and pork, bison, egg whites, and tofu.

A person measuring their waist.

#3: Carbohydrates

The Overnight diet meal plan is a low-carb weight loss diet. However, there are certain approved carbohydrates that are termed “lean carbs, “ as per Dr. Apovian.

These include the fruit and non-starchy vegetables discussed, as well as whole grains only.

#4: Non-Nutritive Sweeteners

While all added sugars are removed from the diet, certain noncaloric sweeteners are on the Overnight diet food list.

These include Splenda, xylitol, Monk fruit sweetener, Truvia, and Stevia.

Overnight Diet 1-Day Power Up

On the Overnight Diet Power Up Day, you can only have smoothies instead of solid food.

The smoothies are made with unlimited fruits, vegetables, nonfat milk, and/or protein powder. The Overnight diet book has smoothie recipes that you can follow.

This eating plan removes all processed foods and foods that are high in sugar as these are not considered to be “real foods.“

Here are the main foods you cannot eat on the overnight diet program:

Foods To Avoid On The Overnight Diet Program

  • Refined carbohydrates: These foods lack protein and fiber, so they are not satiating and can increase hunger. Examples include white bread, white pasta, breakfast cereal, granola bars, pancake mix, crackers, etc. 
  • Processed foods: All types of processed foods such as chips, cookies, frozen meals, boxed macaroni and cheese, fruit snacks, candy, processed meats, French fries, pretzels, rice cakes, chicken nuggets, etc.
  • Foods with added sugar: Candy, baked goods, fruit juice, sweetened applesauce, and even natural sugar, such as honey or maple syrup.
A person lacing up their shoe.

Exercise and Sleep

In addition to the Overnight diet eating plan, an exercise plan involves a 21-minute workout to be completed at least four times per week.

Central to the Overnight diet program is the importance of getting enough quality sleep every night.

This is because studies have shown that lack of sleep increases levels of the hunger hormone, ghrelin.2Broussard, J. L., Kilkus, J. M., Delebecque, F., Abraham, V., Day, A., Whitmore, H. R., & Tasali, E. (2015). Elevated ghrelin predicts food intake during experimental sleep restriction. Obesity24(1), 132–138. https://doi.org/10.1002/oby.21321

‌By getting enough sleep, you are able to control your appetite better and hopefully support weight loss.

‌Lack of sleep also increases cortisol levels, the stress hormone.3Hirotsu, C., Tufik, S., & Andersen, M. L. (2015). Interactions between sleep, stress, and metabolism: From physiological to pathological conditions. Sleep Science8(3), 143–152. https://doi.org/10.1016/j.slsci.2015.09.002

High levels of cortisol have been associated with inflammation and increased fat storage, particularly in the abdominal area.

Additionally, if you are tired, you will have less energy and may be inclined to make poor food choices, particularly choosing high-sugar foods for a quick burst of energy. Y

You may also be less inclined to be physically active and move your body, which will decrease your caloric expenditure.4Dolezal, B. A., Neufeld, E. V., Boland, D. M., Martin, J. L., & Cooper, C. B. (2017). Interrelationship between Sleep and Exercise: A Systematic Review. Advances in Preventive Medicine. https://www.hindawi.com/journals/apm/2017/1364387/

‌Altogether, these effects of insufficient sleep can contribute to weight gain and will certainly make losing weight more difficult.

A person in bed.

Is the Overnight Diet Good for Weight Loss and Health?

As with any weight loss diet, there are some pros and cons to the Overnight diet program.

Here are some of the potential benefits and good aspects of the Overnight diet for weight loss and health:

  • Focus on getting enough sleep and exercise will help support overall health and weight loss.
  • High protein diets have been associated with better satiety, conservation of lean body mass, and weight loss.
  • Unlimited consumption of fruits and vegetables can give dieters a feeling of freedom and like they aren’t restricted. Plus, there is an abundance of evidence to suggest any health benefits of eating a lot of nutrient-dense foods like vegetables due to the antioxidants, vitamins, minerals, fiber, and water.
  • Not needing to count calories can be helpful for some people.
  • Can result in weight loss due to the caloric deficit.
  • There are no restrictions on when you can eat during the day.
A coop of protein.

There are also some potential downsides.

  • High-protein diets are not suitable for certain individuals, particularly those with kidney issues or osteoporosis.
  • The smoothie day can be not feasible for people who are on the go.
  • The diet is pretty restrictive with both calories and certain nutrients, such as healthy fats, when you look at the Overnight diet recipes provided in the book.
  • Weight loss that is too extreme or rapid can be unhealthy and unsustainable, and the suggested Overnight diet weight loss rate is too fast.
  • May not be suitable for people with difficulty digesting fruits and veggies or who can’t have carbohydrates.

If you are trying to lose weight or reduce your risk of diseases, consider working with a registered dietitian, nutritionist, and doctor to find the best diet and exercise program for your needs.

If you are looking for more options and are undecided about which diet plan is right for you, take a look at our guide to Intermittent Fasting here.

A person speaking with a nutritionist.

References

  • 1
    Broussard, J. L., Kilkus, J. M., Delebecque, F., Abraham, V., Day, A., Whitmore, H. R., & Tasali, E. (2015). Elevated ghrelin predicts food intake during experimental sleep restriction. Obesity24(1), 132–138. https://doi.org/10.1002/oby.21321
  • 2
    Broussard, J. L., Kilkus, J. M., Delebecque, F., Abraham, V., Day, A., Whitmore, H. R., & Tasali, E. (2015). Elevated ghrelin predicts food intake during experimental sleep restriction. Obesity24(1), 132–138. https://doi.org/10.1002/oby.21321
  • 3
    Hirotsu, C., Tufik, S., & Andersen, M. L. (2015). Interactions between sleep, stress, and metabolism: From physiological to pathological conditions. Sleep Science8(3), 143–152. https://doi.org/10.1016/j.slsci.2015.09.002
  • 4
    Dolezal, B. A., Neufeld, E. V., Boland, D. M., Martin, J. L., & Cooper, C. B. (2017). Interrelationship between Sleep and Exercise: A Systematic Review. Advances in Preventive Medicine. https://www.hindawi.com/journals/apm/2017/1364387/
Photo of author
Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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