Why Am I Not Losing Weight? Your Body's Reaction to Not Eating

If you’ve stopped losing weight on a low-calorie diet, it can be tempting to continue reducing calories or try extreme fasting diets to shed the pounds. However, these types of eating plans can trigger the body’s starvation response, negatively impacting your metabolic rate. 

It’s best to work with a registered dietitian to identify a realistic weight management plan involving nutritious foods, regular exercise, stress management, and adequate hydration. 

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Understanding Your Body's Response to Not Eating Enough

The human body has many defense mechanisms in place to protect you against starvation. When your calorie intake is very low for an extended period of time, a couple of things happen. 

First, your metabolic rate and body temperature decrease to conserve energy. You burn fewer calories to do the same daily activities, so your brain has enough energy to function. 

Hunger and food cravings also increase due to changes in the gut hormones that regulate appetite. These changes also cause a decreased sense of fullness. 

Initially, the body attempts to burn fat mass instead of muscle for energy in a process called ketosis. Once fat stores are depleted, the body shifts to burning lean mass as the primary energy source. 

If left unchecked, starvation can result in muscle wasting, vitamin deficiencies, malnutrition, and eventually death. 

What Happens If You Don't Eat Enough?

If you completely stop eating for a day or two at a time in an attempt to lose weight, which is a strategy used in some fad fasting diets, you’ll start to notice several symptoms, such as: 

• Increased hunger.
• Fatigue. 
• Difficulty focusing. 
• Weight loss.

Though you may lose weight in the short term, weight regain is common once the fasting diet has ended. In addition, it can feed into a cycle of restricting and then overeating or binging, which is a predictor of weight gain and disordered eating.

If you continue fasting or eating very small amounts of food for many days, you’ll begin to experience more serious symptoms, like:

• Stomach cramps.
• Fainting.
• Hair loss.
• Muscle weakness. 
• Cold hands and feet.
• Slow wound healing. 
• Poor immune function. 

These are signs of a deeper issue, such as eating disorders like anorexia nervosa. If you or a loved one are experiencing the above symptoms as a result of restrictive eating, talk to a doctor right away. 

What Factors Contribute to Not Losing Weight?

Many factors can make it difficult for a person to lose weight, from dietary choices to stress levels to underlying medical conditions. 

While this can be discouraging, your doctor and dietitian can create a plan to help you reach your health goals without turning to extreme fasting diets and disordered eating behaviors. 

Stress and Cortisol Levels

Chronic psychological stress can cause an increase in the hormone cortisol, which can, in turn, make it difficult to lose weight.

High-stress levels can also increase cravings for highly palatable foods, especially desserts, sugar-sweetened beverages, fried foods, and alcohol. In addition, chronic stress is associated with lower levels of exercise.   

Interestingly, restrictive low-calorie diets (1200 calories per day) have been shown to increase psychological stress and cortisol levels, which can negatively impact weight management efforts. 

Metabolic Adaptation

Because of the mechanisms in place to prevent starvation, your metabolism can adapt to a low-calorie diet over time. Your metabolic rate eventually decreases, so you no longer lose weight at the original calorie deficit. 

This can be incredibly discouraging because you can experience a weight loss plateau despite maintaining your eating and exercise plan. It can lead many people to decrease their calorie intake further, which only continues lowering the metabolic rate, making it harder to lose weight. 

Dehydration

Not drinking enough water may hinder weight management efforts. Research shows that interventions like increasing total water intake, drinking water before meals, and replacing calorie-containing beverages with water can improve weight loss results. 

Water has a thermogenic effect, meaning it can increase the metabolic rate. One small study from 2003 found that drinking two liters (64 ounces) of water daily can increase energy expenditure by almost 100 calories per day.

Poor Diet

Eating too many or too few calories can make it difficult to lose weight. However, the composition of your diet, not just the overall calorie intake, can also influence your weight management outcomes. 

Research shows that high-protein diets can be effective for weight management because a greater protein intake boosts the metabolic rate. Dietary protein also helps regulate hunger by increasing satiety after a meal. 

In addition, limiting your consumption of sugar-sweetened beverages, like soda and juice, can help support weight management goals. 

Experts recommend focusing on your overall dietary pattern to ensure a balance of minimally processed lean proteins, whole-grain carbohydrates, healthy fats, fruits, and vegetables. 

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Lack of Exercise or Movement

Both aerobic and resistance exercises can benefit weight management efforts. Resistance or strength exercises can help combat the loss of muscle mass and the decreases in metabolic rate that can occur during weight loss. 

Studies show that aerobic or cardio exercise can play a role in reducing abdominal fat. Experts recommend at least 150 minutes per week of moderate-intensity aerobic activity. 

Underlying Medical Issues

Sometimes, an underlying medical condition may influence your metabolism, resulting in weight gain or difficulty managing weight. Common examples include:

• Hypothyroidism. 
• Polycystic ovarian syndrome (PCOS.)
• Menopause. 
• Binge-eating disorder. 
• Obstructive sleep apnea. 

Certain medications can also cause metabolic changes or increases in appetite, like antidepressants. 

Calculating Your Calorie Needs

You can calculate your calorie needs using a validated formula, such as Mifflin St. Jeor. You’ll input information like your age, sex, height, weight, and activity level to find the estimated daily calories needed to maintain your weight. 

Remember that these equations estimate calorie needs and cannot account for factors that may alter metabolic rate, like yo-yo dieting or PCOS. 

Most weight management plans involve a calorie deficit of around 500 calories daily. A registered dietitian can help you find the right calorie level and create a sustainable, healthy plan to manage your weight. 

Experts recommend avoiding diets below 1200 calories for females and 1500 calories for males to ensure adequate nutrition and metabolic function. 

Consider scheduling an appointment with a registered dietitian through Nourish for individualized eating advice for weight management. 

When to See a Doctor About Your Weight Loss Plateau

If you’ve tried multiple eating and exercise plans for weight management, but your weight is stable or increasing, it may be time to seek your doctor’s opinion. Your physician can do a workup to determine if there are any underlying factors influencing your weight. 

You may also want to work with a doctor or registered dietitian if you’ve successfully lost weight but encountered a plateau. Your healthcare team can help you identify areas to focus on to move forward. 

Takeaway

It can be frustrating to follow a low-calorie diet only to find that the number on the scale stays the same. Sometimes, difficulty losing weight can happen due to overly restrictive low-calorie or fasting diets. 

In other cases, factors like diet, exercise, stress, metabolism, and underlying medical conditions may influence your ability to lose weight. 

Managing Weight Loss with a Dietitian

A registered dietitian can help you create a healthy weight management plan and advise you on food choices, exercise regimen, and calorie needs. 

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