Why Restricting Your Eating May Not Be Working
In today’s weight-conscious world, many people adopt extreme dieting habits in an effort to shed pounds quickly. Among the most common misconceptions is the belief that eating very little or drastically restricting calories is an effective and sustainable way to lose weight. While it might seem logical that reducing food intake will lead to weight loss, not eating enough can have serious consequences on both your body and mind.
What Happens When You Don’t Eat Enough?
Eating too few calories, also known as undereating, can trigger a series of physiological responses that may hinder your weight loss efforts and, more importantly, affect your overall health. While a caloric deficit (eating fewer calories than your body needs to maintain weight) is necessary for weight loss, drastically reducing caloric intake can cause your metabolism to slow down, your body to enter “starvation mode,” and other negative effects on your mental and physical health.
1. Slowed Metabolism
When you severely restrict your calories, your body perceives this as a potential threat to survival. To conserve energy, your metabolism may slow down, making it harder to burn calories efficiently. This response is often referred to as adaptive thermogenesis (Ravussin & Lillioja, 1988). Essentially, the body becomes more efficient at using the few calories you provide, which means you burn fewer calories even at rest.
The result? Weight loss may plateau or even reverse as your body adjusts to the lower intake. In some cases, people who drastically cut their calories might find themselves gaining weight once they resume a normal eating pattern, because their metabolism has become so sluggish.
2. Nutrient Deficiencies
When you don’t eat enough, you’re also likely not getting the essential nutrients your body needs to function properly. Caloric restriction often leads to deficiencies in vitamins, minerals, and other nutrients, which can have serious long term effects on health. For example, a lack of key nutrients like iron, calcium, vitamin D, and omega-3 fatty acids can lead to weakened immunity, bone loss, poor skin health, and fatigue (Krogh et al., 2010).
Deficiencies in essential nutrients can impair the function of important systems in your body, such as the cardiovascular, musculoskeletal, and nervous systems. Long term nutrient deficiencies can also lead to conditions like anaemia, osteopenia, and hormonal imbalances.
3. Hormonal Imbalance
Your body’s hormone levels are tightly regulated by nutrition, and when you don’t eat enough, your hormones can become imbalanced. For example, reduced caloric intake can lower levels of leptin, a hormone responsible for regulating hunger and energy balance (Havel, 2001). As leptin decreases, your body may trigger increased hunger signals, making it even harder to stick to a restricted eating plan.
In women, undereating can lead to disruptions in oestrogen and progesterone levels, which can affect menstrual cycles and fertility. Severe caloric restriction can even lead to amenorrhoea (the absence of periods), which indicates a significant imbalance in reproductive hormones (Frisch et al., 1991).
4. Muscle Loss
Another consequence of not eating enough is muscle loss. When your body isn’t getting enough energy from food, it turns to stored fat and muscle tissue for fuel. This is particularly true if you are not getting adequate protein. Muscle loss can be especially problematic because muscles are metabolically active, meaning they help burn calories even when you’re at rest.
The loss of muscle mass can lower your basal metabolic rate (BMR), making it harder to maintain weight loss in the long term. This can create a cycle where you continually lose muscle, slow down your metabolism, and experience weight gain once you return to a normal eating pattern.
5. Mental Health Impacts
Not eating enough can also take a toll on your mental health. Chronic caloric restriction has been linked to mood disturbances, increased irritability, anxiety, and depression (Klonoff & Karasik, 1992). The brain requires energy to function properly, and when you aren’t providing enough calories, cognitive function and emotional regulation can suffer.
Many people who severely restrict calories also develop unhealthy relationships with food, including disordered eating patterns like binge eating, emotional eating, and obsessive thoughts about food. This can lead to a vicious cycle where the person tries to restrict even more, only to fall into binge-eating episodes when the body’s hunger cues become overwhelming.
The Dangers of Extreme Dieting
Extreme dieting practices, such as skipping meals, using very low-calorie diets, or relying on fad diets (e.g., juice cleanses, detox diets), are often marketed as quick fixes for weight loss. However, these approaches are not sustainable and can have significant negative consequences on health.
Crash diets that promote rapid weight loss usually result in water loss and muscle loss, rather than fat loss. Once you resume eating normally, much of the weight is regained, often leading to a cycle of weight loss and gain that is difficult to break. This is commonly referred to as the yo-yo diet effect, and it can have detrimental effects on metabolism, muscle mass, and overall health (Müller et al., 2013).
Moreover, extreme dieting can affect your ability to recognise true hunger and fullness cues, making it harder to develop a balanced and healthy relationship with food.
How to Lose Weight in a Healthy, Sustainable Way
Instead of drastically cutting calories, there are healthier and more sustainable ways to manage your weight. Here are some tips for effective, long term weight management:
1. Focus on Nutrient-Dense Foods
Rather than focusing solely on cutting calories, prioritise nutrient-dense foods that provide your body with essential vitamins, minerals, and macronutrients. These include vegetables, fruits, plant proteins, whole grains, and healthy fats. Nutrient-dense foods not only support overall health but also help you feel fuller for longer, reducing the likelihood of overeating.
2. Eat Regularly and Consistently
Eating regular meals and snacks throughout the day helps regulate blood sugar levels and prevent feelings of extreme hunger. Skipping meals can cause overeating later on, which can undermine your weight loss goals.
3. Incorporate Physical Activity
Exercise is a key component of healthy weight management. Strength training exercises can help you preserve muscle mass and maintain a higher metabolism. Cardiovascular exercise, such as walking, biking, or swimming, can also help burn calories and improve heart health (Thyfault & Booth, 2011).
4. Be Patient and Set Realistic Goals
Sustainable weight loss takes time. Aim for a gradual weight loss of 0.5kg – 1kg per week. Rapid weight loss is often unsustainable and may lead to negative physical and emotional effects. It’s essential to focus on long term health and wellness rather than short term, drastic results.
While it may seem counterintuitive, not eating enough to lose weight can actually hinder your weight loss efforts and lead to serious health problems. Extreme calorie restriction can slow your metabolism, cause nutrient deficiencies, disrupt your hormones, and affect your mental health. Instead of adopting drastic dieting habits, it’s important to focus on balanced, nutrient-dense eating, regular physical activity, and a sustainable approach to weight management. By prioritising your health and wellbeing, you can achieve your weight loss goals in a safe and effective way.
References
Frisch, R. E., McArthur, J. W., & Schenker, J. G. (1991). Hormonal, metabolic, and nutritional determinants of fertility. Nutrition and Metabolism, 41(2), 55-75. https://doi.org/10.1016/0163-4381(91)90040-3
Havel, P. J. (2001). Role of leptin in regulating energy balance. American Journal of Clinical Nutrition, 74(3), 466-471. https://doi.org/10.1093/ajcn/74.3.466
Klonoff, D. C., & Karasik, A. (1992). Psychological effects of caloric restriction and the treatment of obesity. International Journal of Obesity, 16(1), 31-37.
Krogh, J., Saltin, B., & Boushel, R. (2010). Nutritional deficiency and physical performance in the obese: The impact of energy restriction. Journal of Obesity, 2010(1), 1-7. https://doi.org/10.1155/2010/921978
Müller, M. J., Bosy-Westphal, A., & Klaus, S. (2013). Long-term consequences of weight cycling: What do we know? Current Diabetes Reports, 13(6), 1025-1030. https://doi.org/10.1007/s11892-013-0431-2
Ravussin, E., & Lillioja, S. (1988). Determinants of 24-hour energy expenditure in man. Metabolism, 37(5), 470-473. https://doi.org/10.1016/0026-0495(88)90106-7
Thyfault, J. P., & Booth, F. W. (2011). Lack of exercise is a major cause of chronic diseases. Comprehensive Physiology, 1(4), 1587-1603. https://doi.org/10.1002/cphy.c1002