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The ABC Diet promises to promote rapid weight loss, making it an enticing idea to some.
However, it achieves this by severely limiting your daily calorie intake, which can seriously damage your health.
In this article, you’ll learn what the ABC Diet plan is, what the ABC Diet schedule looks like, why it’s terrible for your health, the truth about the ABC Diet’s results, a healthier and more sustainable way to lose weight quickly, and more.
What Is the ABC Diet (“Ana Boot Camp Diet”)?
The ABC Diet plan, or “Ana Boot Camp Diet,” is a highly restrictive and potentially dangerous starvation diet that promotes weight loss by severely limiting calorie intake.
It’s called the Ana Boot Camp Diet because many consider it a gateway to anorexia, a life-threatening eating disorder.
The ABC Diet lasts 50 days, during which time you vary your calorie intake, eating between 0 and 800 calories daily. The ABC diet schedule has 5 phases that determine the number of calories you eat daily, increasing or decreasing in 50-to-100-calorie increments depending on the phase and day.
Contrary to popular belief, the ABC Diet plan doesn’t promote weight loss by tricking the body’s metabolism to run faster. Instead, the extreme calorie restriction starves the body, forcing it to use stored fat and muscle for energy, which slows metabolic rate and harms overall health.
ABC Diet Schedule
The ABC Diet schedule splits the 50 days into 5 phases. These phases vary in length from 4-to-15 days.
During each phase, you must not exceed the daily calorie allowances below:
Phase 1: Day 1-to-10
- Day 1: 500 calories
- Day 2: 500 calories
- Day 3: 300 calories
- Day 4: 400 calories
- Day 5: 100 calories
- Day 6: 200 calories
- Day 7: 300 calories
- Day 8: 400 calories
- Day 9: 500 calories
- Day 10: Zero calories
Phase 2: Day 11-to-20
- Day 11: 150 calories
- Day 12: 200 calories
- Day 13: 400 calories
- Day 14: 350 calories
- Day 15: 250 calories
- Day 16: 200 calories
- Day 17: Zero calories
- Day 18: 200 calories
- Day 19: 100 calories
- Day 20: Zero calories
Phase 3: Day 21-to-30
- Day 21: 300 calories
- Day 22: 250 calories
- Day 23: 200 calories
- Day 24: 150 calories
- Day 25: 100 calories
- Day 26: 50 calories
- Day 27: 100 calories
- Day 28: 200 calories
- Day 29: 200 calories
- Day 30: 300 calories
Phase 4: Day 31-to-34
- Day 31: 800 calories
- Day 32: Zero calories
- Day 33: 250 calories
- Day 34: 350 calories
Phase 5: Day 35-to-50
- Day 35: 450 calories
- Day 36: Zero calories
- Day 37: 500 calories
- Day 38: 450 calories
- Day 39: 400 calories
- Day 40: 350 calories
- Day 41: 300 calories
- Day 42: 250 calories
- Day 43: 200 calories
- Day 44: 200 calories
- Day 45: 250 calories
- Day 46: 200 calories
- Day 47: 300 calories
- Day 48: 200 calories
- Day 49: 150 calories
- Day 50: Zero calories
Does the ABC Diet Work?
When asking if the ABC Diet works, it’s crucial to define what “working” means in the context of diet and health.
You’ll definitely lose weight on the ABC Diet plan because it encourages you to eat far fewer calories than most people need to function, forcing your body to fuel its processes using stored energy in fat and muscle.
However, the initial weight loss comes with significant health risks, including potential malnutrition, a weakened immune system, muscle and bone loss, and organ damage. Moreover, it disrupts the body’s metabolism, which can make future weight loss more challenging.
The ABC Diet also poses psychological dangers. It can promote an unhealthy relationship with food, increasing your risk of developing eating disorders like anorexia.
Besides the physical and mental health risks, the ABC Diet is unlikely to help you maintain a lower weight long-term. While you may rapidly lose weight in the beginning, unless you change your eating and lifestyle habits, you’ll just as quickly regain any lost weight once the diet ends and you return to your old ways.
The Side Effects and Risks of the ABC Diet
The risks of the ABC diet far outweigh any of the ABC diet’s benefits. Side effects of following a very low-calorie diet include:
- Fatigue
- Dizziness
- Abdominal pain or bloating
- Hindered immune function
- Dry skin, brittle hair, and weakened bones
- Increased risk of, and death from, bacterial infections
- Low heart rate and blood pressure
- Increased risk of heart and kidney failure
- Low blood sugar
- Increased insulin resistance
- Hormonal imbalances
- Dehydration
- Pancreatitis
- Insomnia and sleep apnea
- Increased risk of suicide
- Increased risk of premature death
The Reality of ABC Diet Results
While you might think you’ll love your ABC Diet results, it’s important to understand that any benefits you experience will be short-lived and come with significant drawbacks.
For instance, after trudging through 50 days of the starvation meal plan, most have an overwhelming and insatiable hunger, which often leads people to rampantly overeat and undo any progress made during the diet.
And it definitely doesn’t help your metabolism.
Studies show that rapid weight loss, particularly from low-calorie dieting, causes your metabolic rate to dip. It also often leads to muscle loss, and since muscles are “metabolically active” and help burn calories, losing them causes your metabolic rate to nosedive further.
For example, research shows that calorie-restricted dieting may cause a long-term reduction in metabolic rate of up to 7-to-10%.
As a result, future weight loss may be more challenging, and you’ll likely feel weak, lethargic, and generally unwell.
How to Safely and Healthily Lose Weight Fast (Without the ABC Diet)
Effective and healthy weight loss involves losing fat while preserving muscle.
Like most crash diets, however, the ABC Diet leads to substantial loss of both fat and muscle, which undermines your health and compromises long-term weight management. To safely and healthily reach your goal weight fast, you need a plan that helps you lose fat and maintain muscle.
Here’s everything you need to know:
Diet
When trying to lose fat and retain muscle, high-protein dieting beats low-protein diets in every way.
Specifically, you should eat about 1-to-1.2 grams of protein per pound of body weight per day.
And if you’re very overweight (25%+ body fat in men and 30%+ in women), reduce your protein intake to around 40% of your total calories per day.
(If you want even more specific advice about how many calories, how much of each macronutrient, and which foods you should eat to reach your health and fitness goals, take the Legion Diet Quiz. In less than a minute, you’ll know exactly what diet is right for you. Click here to check it out.)
Exercise
Aim to lift weight 3-to-5 times weekly.
To maximize the fat-burning effects of weightlifting, focus on the following:
- Compound exercises: A compound exercise targets multiple muscle groups at once, like squats, pull-ups, and dips. Studies show that compound exercises produce the greatest increases in metabolic rate, muscle mass, and strength, making it the best exercise for increasing fat loss.
- Heavy weightlifting: Research shows that training with 75-to-85% of your one-rep max (weights that you can do 6-to-12 reps with before failing) builds more muscle and burns more fat than training with lighter weights.
- Progressive overload: Add weight or reps to every exercise in every workout to maximize muscle-building and fat-burning. This is known as progressive overload, and it’s the most important driver of muscle growth.
And if you’d like even more specific advice about how often you should train, what exercises you should do, and for how many sets and reps to reach your health and fitness goals, take the Legion Strength Training Quiz, and in less than a minute, you’ll know the perfect strength training program for you. Click here to check it out.
FAQ #1: What are the benefits of the ABC Diet?
The primary benefit touted by proponents of the ABC Diet is rapid weight loss. However, the significant health risks associated with the diet overshadow this benefit.
FAQ #2: Is the ABC Diet safe?
No, the ABC Diet is not safe. It involves severe calorie restriction, which can lead to malnutrition, muscle loss, a weakened immune system, and potential long-term damage to vital organs. The diet also increases the risk of developing eating disorders.
FAQ #3: Why is it called the ABC Diet?
The ABC Diet stands for “Ana Boot Camp” Diet. Pro-anorexia communities often use the term “Ana” as shorthand for anorexia.
The name reflects the diet’s extremely restrictive nature and its potential to lead to anorexia, a life-threatening eating disorder.
+ Scientific References
- Herpertz-Dahlmann, Beate, and Brigitte Dahmen. “Children in Need—Diagnostics, Epidemiology, Treatment and Outcome of Early Onset Anorexia Nervosa.” Nutrients, vol. 11, no. 8, 16 Aug. 2019, p. 1932, https://doi.org/10.3390/nu11081932.
- Mohan, Viswanathan, and Shilpa Joshi. “Pros & Cons of Some Popular Extreme Weight-Loss Diets.” Indian Journal of Medical Research, vol. 148, no. 5, 2018, pp. 642–647, www.ncbi.nlm.nih.gov/pmc/articles/PMC6366252/, https://doi.org/10.4103/ijmr.ijmr_1793_18.
- Fothergill, Erin, et al. “Persistent Metabolic Adaptation 6 Years after “the Biggest Loser” Competition.” Obesity (Silver Spring, Md.), vol. 24, no. 8, 2016, pp. 1612–9, www.ncbi.nlm.nih.gov/pubmed/27136388, https://doi.org/10.1002/oby.21538.
- Memon, Areeba N., et al. “Have Our Attempts to Curb Obesity Done More Harm than Good?” Cureus, vol. 12, no. 9, 6 Sept. 2020, www.cureus.com/articles/38393-have-our-attempts-to-curb-obesity-done-more-harm-than-good, https://doi.org/10.7759/cureus.10275.
- Spadaro, O., et al. “Caloric Restriction in Humans Reveals Immunometabolic Regulators of Health Span.” Science, vol. 375, no. 6581, 11 Feb. 2022, pp. 671–677, https://doi.org/10.1126/science.abg7292. Accessed 16 Feb. 2022.
- Fontana, Luigi, et al. “Effect of Long-Term Calorie Restriction with Adequate Protein and Micronutrients on Thyroid Hormones.” The Journal of Clinical Endocrinology & Metabolism, vol. 91, no. 8, 1 Aug. 2006, pp. 3232–3235, https://doi.org/10.1210/jc.2006-0328. Accessed 31 Dec. 2021.
- Fichter, Manfred Maximilian, and Norbert Quadflieg. “Mortality in Eating Disorders – Results of a Large Prospective Clinical Longitudinal Study.” The International Journal of Eating Disorders, vol. 49, no. 4, 2016, pp. 391–401, www.ncbi.nlm.nih.gov/pubmed/26767344, https://doi.org/10.1002/eat.22501.
- Anthonius, Tom, et al. “The Impact and Utility of Very Low-Calorie Diets: The Role of Exercise and Protein in Preserving Skeletal Muscle Mass.” Current Opinion in Clinical Nutrition and Metabolic Care, 8 Sept. 2023, https://doi.org/10.1097/mco.0000000000000980. Accessed 29 Sept. 2023.
- Casanova, Nuno, et al. “Metabolic Adaptations during Negative Energy Balance and Their Potential Impact on Appetite and Food Intake.” Proceedings of the Nutrition Society, vol. 78, no. 3, 14 Feb. 2019, pp. 279–289, https://doi.org/10.1017/s0029665118002811. Accessed 27 Nov. 2020.
- Stewart, Tiffany M., et al. “The Complicated Relationship between Dieting, Dietary Restraint, Caloric Restriction, and Eating Disorders: Is a Shift in Public Health Messaging Warranted?” International Journal of Environmental Research and Public Health, vol. 19, no. 1, 3 Jan. 2022, p. 491, https://doi.org/10.3390/ijerph19010491. Accessed 29 Jan. 2022.
- Ochner, Christopher N., et al. “Biological Mechanisms That Promote Weight Regain Following Weight Loss in Obese Humans.” Physiology & Behavior, vol. 120, Aug. 2013, pp. 106–113, https://doi.org/10.1016/j.physbeh.2013.07.009.
- Anthonius, Tom, et al. “The Impact and Utility of Very Low-Calorie Diets: The Role of Exercise and Protein in Preserving Skeletal Muscle Mass.” Current Opinion in Clinical Nutrition and Metabolic Care, 8 Sept. 2023, https://doi.org/10.1097/mco.0000000000000980. Accessed 29 Sept. 2023.
- McClave, Stephen A., and Harvy L. Snider. “Dissecting the Energy Needs of the Body.” Current Opinion in Clinical Nutrition and Metabolic Care, vol. 4, no. 2, Mar. 2001, pp. 143–147, https://doi.org/10.1097/00075197-200103000-00011.
- Redman, Leanne M., et al. “Metabolic Slowing and Reduced Oxidative Damage with Sustained Caloric Restriction Support the Rate of Living and Oxidative Damage Theories of Aging.” Cell Metabolism, vol. 27, no. 4, Apr. 2018, pp. 805-815.e4, https://doi.org/10.1016/j.cmet.2018.02.019. Accessed 24 July 2019.
- Gil, Saulo, et al. “Acute Muscle Mass Loss Predicts Long-Term Fatigue, Myalgia, and Health Care Costs in COVID-19 Survivors.” Journal of the American Medical Directors Association, vol. 24, no. 1, Jan. 2023, pp. 10–16, https://doi.org/10.1016/j.jamda.2022.11.013. Accessed 17 Feb. 2023.
- Fogarasi, Adam, et al. “The Impact of the Rate of Weight Loss on Body Composition and Metabolism.” Current Obesity Reports, 8 Feb. 2022, https://doi.org/10.1007/s13679-022-00470-4. Accessed 1 Mar. 2022.
- Huovinen, Heikki T., et al. “Body Composition and Power Performance Improved after Weight Reduction in Male Athletes without Hampering Hormonal Balance.” Journal of Strength and Conditioning Research, vol. 29, no. 1, Jan. 2015, pp. 29–36, https://doi.org/10.1519/jsc.0000000000000619.
- Farinatti, Paulo TV, and Antonio G Castinheiras Neto. “The Effect of Between-Set Rest Intervals on the Oxygen Uptake during and after Resistance Exercise Sessions Performed with Large- and Small-Muscle Mass.” Journal of Strength and Conditioning Research, vol. 25, no. 11, Nov. 2011, pp. 3181–3190, https://doi.org/10.1519/jsc.0b013e318212e415.
- MARX, JAMES O., et al. “Low-Volume Circuit versus High-Volume Periodized Resistance Training in Women.” Medicine and Science in Sports and Exercise, Apr. 2001, pp. 635–643, https://doi.org/10.1097/00005768-200104000-00019.
- Schoenfeld, Brad J. “The Mechanisms of Muscle Hypertrophy and Their Application to Resistance Training.” Journal of Strength and Conditioning Research, vol. 24, no. 10, 2010, pp. 2857–72, https://doi.org/10.1519/JSC.0b013e3181e840f3.
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