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How many calories is dangerously low?

When it comes to calorie intake, consuming too few calories can be just as dangerous as consuming too many. But how low is too low when it comes to your daily caloric intake? Getting the right amount of calories is key for supporting energy levels, overall health, and a healthy body weight.

What is the recommended minimum calorie intake?

The recommended minimum calorie intake can vary based on factors like age, gender, activity level, and health status. However, most health organizations suggest the following minimum calorie intakes:

  • Women: 1,200 calories per day
  • Men: 1,500 calories per day

Eating below these minimums routinely can put you at risk for nutrient deficiencies, loss of muscle mass, fatigue, hormonal imbalances, and other problems. For most people, dipping below 1,000 calories daily is considered very dangerous and requires medical supervision.

What happens when you eat too few calories?

Eating too few calories over a prolonged period can lead to a condition known as starvation mode. When this happens, your body starts breaking down muscle and fat stores for energy and your metabolism slows down to conserve calories. Effects of very low calorie intake and starvation mode can include:

  • Fatigue and weakness
  • Headaches
  • Dizziness
  • Irritability and mood changes
  • Difficulty concentrating
  • Reduced immune function
  • Hair loss
  • Constipation
  • Loss of menstrual period in women
  • Slower wound healing
  • Electrolyte imbalances
  • Irregular heartbeat
  • Muscle loss and reduced strength
  • Brittle bones and increased fracture risk

Over time, restricting calories too much can also lead to serious complications like anemia, heart failure, infertility, and even death.

Health risks of very low calorie intake

Some specific health risks associated with consuming dangerously low amounts of calories include:

  • Nutrient deficiencies – Not getting enough calories makes it difficult to meet daily nutrient needs for vitamins, minerals, protein, healthy fats, and more. Deficiencies can cause symptoms like changes in hair, skin, and nails, impaired wound healing, and altered immune function.
  • Electrolyte imbalances – Electrolytes like sodium, potassium, calcium, and magnesium are essential for proper fluid balance, muscle function, nerve signaling, and more. Very low calorie intake can deplete levels and lead to fatigue, headaches, cramping, and irregular heart rhythms.
  • Anemia – Consuming inadequate calories and specific nutrients like iron can contribute to anemia, which causes fatigue, pale skin, dizziness, and shortness of breath.
  • Heart problems – Starvation mode slows the heart rate and reduces blood pressure. If calorie restriction is extreme, it can lead to dangerous irregular heart rhythms and heart failure.
  • Loss of bone density – Very low calorie diets provide inadequate calories and nutrients for bone health. This can cause osteopenia or osteoporosis, increasing fracture risk.
  • Severe dehydration – Extreme calorie restriction can lead to dehydration, reducing blood volume and causing electrolyte imbalances, kidney damage, seizures, and death if left untreated.
  • Refeeding syndrome – Refeeding syndrome describes metabolic shifts that occur when resuming normal calorie intake after prolonged starvation. It can lead to heart, lung and kidney complications.

Very low calorie intake warning signs

Signs that someone may be consuming a dangerously low number of calories include:

  • Fatigue, dizziness, weakness
  • Difficulty concentrating and impaired cognition
  • Irritability, anxiety, depression
  • Food obsession and abnormal eating behaviors
  • Significant unplanned weight loss
  • Feeling cold frequently or trouble maintaining body temperature
  • Dry skin, hair loss, brittle nails
  • Constipation, abdominal pain
  • Absent or irregular menstrual periods in women
  • Fainting spells or heart palpitations
  • Electrolyte abnormalities

If you notice these warning signs or rapid unexplained weight loss, it is important to see a doctor right away. Professional medical and mental health support is often needed to restore a healthy relationship with food and normalize eating patterns.

Specific groups at risk for very low calorie intake

Certain groups may be more likely to restrict calories to dangerous levels, including:

  • Those with eating disorders – People with anorexia, bulimia, or other specified feeding/eating disorders purposely restrict intake and are at high risk for complications of low calorie intake.
  • Active individuals or athletes – Competitive athletes, dancers, gymnasts, and those with physically demanding jobs/hobbies may under-fuel their high activity levels.
  • Older adults – Appetite and food intake often decline naturally with age. Low calorie intake increases frailty, fracture, and infection risk in the elderly.
  • Those with chronic illnesses – Diseases like cancer, chronic obstructive pulmonary disease (COPD), dementia, and Parkinson’s can suppress appetite and make eating difficult.
  • Low-income populations – Inability to access or afford food creates risk for calorie inadequacy and malnutrition.
  • Those with depression – Changes in hunger signaling and eating motivation can occur with depression.

Support and intervention focused on normalizing calorie intake and restoring health is especially vital in these high-risk groups.

Health consequences of prolonged very low calorie intake

Over weeks, months or years, the health consequences of severely restricting calories can become increasingly serious and include:

System Affected Potential Health Consequences
Heart and circulation Irregular heart rhythms, low blood pressure, heart failure, shock
Bone Osteopenia, osteoporosis, fractures
Immune system Frequent infections due to reduced white blood cells
Nervous system Neuropathy, seizures, cognitive deficits
Muscles and joints Loss of muscle mass and tone, reduced strength and endurance, increased injury risk
Kidney Kidney failure, electrolyte imbalances
Gastrointestinal system Constipation, bloating, nausea, abdominal pain
Skin Dryness, rashes, hair loss, brittle nails
Reproductive system Menstrual disorders, infertility
Mental health Depression, anxiety, irritability, reduced concentration

Malnutrition from chronically low calorie intake can be life-threatening if severe. Seeking professional treatment is crucial.

When to seek emergency care for low calorie intake

In some cases of very low calorie intake, emergency medical care is necessary. Go to the emergency room or call 911 if you or someone you know has:

  • A heart rate lower than 50 beats per minute
  • Chest pain, palpitations, or fainting
  • Dizziness,confusion, blurry vision, trouble walking or speaking
  • Vomiting or passing blood
  • Seizures
  • Kidney failure symptoms like reduced urination and swelling
  • Rapid, severe weight loss (more than 1-2 lbs per week)
  • Suicidal thoughts or intentions to starve oneself

Low calorie intake severe enough to require emergency treatment can progress quickly to a life-threatening situation. Urgent medical intervention may be needed to stabilize the person and treat complications.

Getting help for low calorie intake and eating disorders

If you or someone you know is purposefully restricting food and showing signs of dangerous calorie inadequacy, professional help is advised, including:

  • Seeing a primary care doctor – Your doctor can check for medical complications and refer you to specialists for nutritional support, counseling, and eating disorder treatment.
  • Consulting with a registered dietitian – Dietitians can provide meal planning guidance to help restore healthy calorie intake and nutrient balance.
  • Getting psychotherapy – Therapists and counselors help address the underlying emotional and mental health aspects of eating disorders.
  • Participating in an eating disorder treatment program – Structured inpatient or outpatient programs provide medical stabilization, psychological counseling, nutrition education and supervised refeeding.
  • Joining an eating disorder support group – Support groups connect you with others struggling with eating disorders to provide community, accountability and resources for recovery.

With professional support, dangerous habits around food and calorie intake can be corrected over time to restore health and prevent serious complications.

Setting appropriate calorie goals during weight restoration

If you have been chronically restricting intake well below calorie needs, establishing appropriate calorie goals is an important part of treatment and weight restoration. This requires:

  • A clinical assessment of your current health status, weight, and nutritional deficiencies
  • Calculating your basal metabolic rate (BMR) to estimate your body’s basic calorie needs for body functions
  • Factoring in additional calories burned through physical activity and exercise
  • Aiming to increase intake gradually by 200-500 calories per day to reach your minimum estimated needs
  • Reassessing calorie goals regularly with your healthcare team as your weight stabilizes
  • Focusing on calorie-dense, nutritious foods to repair nutritional deficiencies
  • Being patient with your body as metabolism normalizes after prolonged restriction
  • Working with dietitians to develop meal plans that meet your new calorie goals
  • Joining peer support communities to stay motivated and accountable

Restoring a healthy relationship with food and your body’s signals of hunger and fullness is a journey. Support from healthcare providers, nutrition professionals, therapists, and those who understand the struggle makes success possible.

Preventing dangerously low calorie intake

You can take proactive steps to ensure you maintain adequate calorie intake to support health:

  • Aim for the recommended minimum calories for your age, gender, size and activity level
  • Practice mindful, intuitive eating and follow internal hunger/fullness cues
  • Include calorie-dense foods like nuts, avocados, full-fat dairy and dried fruit
  • Eat regular, balanced meals and snacks throughout the day
  • Manage stress through relaxation practices rather than restricting food
  • Exercise in moderation without overtraining
  • Seek support if having difficulty maintaining body weight
  • Work with a dietitian or use an app to track calorie intake
  • Rule out underlying medical conditions affecting appetite or absorption
  • Get treatment right away if experiencing symptoms of an eating disorder

Promoting healthy attitudes around food and adequate calorie intake provides the foundation for well-being across physical, mental and social domains.


Restricting calories too severely can be incredibly dangerous. While recommended minimums vary based on individual factors, most adults require at least 1,200-1,500 calories daily to support basic body functions and health. Consuming less than this on a regular basis risks nutrient deficiencies, organ damage, loss of bone and muscle mass, and possibly even death in extreme cases.

Getting adequate calories is especially important for growing children, teens, active individuals, those recovering from illness, and underweight people. If you or someone you know is purposefully restricting food and showing signs of starvation mode, seek medical care right away. With proper treatment and support, it is possible to restore a healthy relationship with food and prevent the potentially irreversible health consequences of chronic malnutrition.