Can Weight Loss Reduce Fatigue and Increase Energy?

There’s a reason “I was sick and tired of being sick and tired” has become a popular refrain about the motivation to lose weight. Carrying excess weight can have a tremendous impact on your physical and mental energy levels. One study published in the journal Nutrients linked being overweight with fatigue and excessive daytime sleepiness, independent of other factors, and revealed an association between fatigue and elevated BMI and body fat percentage. 

It would seem to reason, then, that weight loss and fatigue reduction would go hand in hand. At the same time, it seems counterintuitive that restricting calories and increasing physical activity could possibly give you more energy and stamina. So what does the evidence suggest about the relationship between body weight and fatigue, and what do we really know about why losing weight gives you more energy? Read on to find out. 

Weight Loss and Fatigue: What Biology Says 

The exact nature of the relationship between weight and energy is still being explored. There are, however, some things that are known about why carrying extra weight can tire you out.

Extra pounds mean extra work

The most obvious reason that excess weight drains you is that a bigger body needs more energy to move through the world. “Excess body fat makes the body work harder. When you walk, you’re carrying around extra weight, which puts more stress on the legs,” says Derek Lipton, RD, founder of Full Circle Sports Nutrition who’s based in Morris Plains, New Jersey.

Being overweight or obese is linked to trouble sleeping

One-third of U.S. adults don’t get enough sleep, according to the Centers for Disease Control and Prevention, and this shortfall has been linked to obesity, among other diseases. A review published in the journal Nutrients found that disturbed sleeping patterns lead people to consume more calories, partly from snacking more on high-carb, high-fat foods. “It’s easy to put sleep on the back burner and play another Netflix episode. But getting seven to nine hours of sleep is an essential habit that should be prioritized,” says Danielle Rancourt, RD, founder of Pivot Nutrition in Grand Forks, North Dakota. “It plays a huge role in promoting health and weight loss.”

In addition, extra pounds increase the risk for certain conditions that hinder quality shut-eye. “People with overweight and obesity are more likely to have sleep apnea,” says Mert Erogul, MD, of Maimonides Medical Center in Brooklyn, New York. The National Heart, Lung, and Blood Institute lists obesity as a “common cause of sleep apnea” due to increased fat in the neck that can block the upper airway. 

Fat cells increase cellular inflammation

A more subtle cause of tiredness when you’re overweight can be systemic inflammation.

Fat cells secrete chemicals that produce an inflammatory response, the Cleveland Clinic reports. Even people whose weight falls in the healthy range of the BMI can have increased inflammation if their body fat percentage is too high, according to a systematic review and meta-analysis published in Frontiers in Immunology. And Harvard Medical School reports that long-term, low-grade inflammation is associated with greater fatigue. “High body fat percentages also impair blood flow and increase inflammation, making you feel more tired with everyday tasks,” says Lipton.

Excess weight is comorbid with other health conditions

If you’re overweight or obese, you may have a condition that independently causes fatigue — and you might not even know it. Roughly 38 percent of U.S. adults have prediabetes, and almost 80 percent of them aren’t aware of their condition, according to an article in U.S. Pharmacist. Fatigue is a common symptom of prediabetes, according to the Mayo Clinic. And prediabetes isn’t the only condition your weight can put you at risk for.

“Obesity is a major cause of many common health conditions, including diabetes and heart disease. When blood sugar and blood pressure, for example, are out of control, it can take a big toll on your energy levels,” says Lipton. 

How Excess Weight Can Lead to Mental and Emotional Fatigue

Anyone on a weight loss journey understands that it can be extremely emotional. And scientific research bears out the low moods that can come with being unhappy with one’s size. A review of the literature published in the journal Psychiatry Investigation suggests a strong association between obesity and depression, and the National Institute of Mental Health lists “decreased energy, fatigue, or feeling slowed down” as one of the symptoms of depression.

On the flip side, losing weight can make a big difference in your emotional life. “People who lose weight on purpose may feel energized by the success and may experience renewed motivation,” says Dr. Erogul.

Will Losing Weight Help Reduce Fatigue?

Weight loss can help reduce fatigue. If excess pounds cause sleep apnea or other disturbances, you’ll start sleeping better and feeling more energized during the day as you slim down. As your weight decreases, your markers of inflammation will also fall, helping you feel better all around. Losing as little as about two pounds in a month caused a significant reduction in inflammatory markers in individuals with overweight and obesity, according to some past research. 

“An increase in energy is often one of the first things people notice when they start losing weight,” says Rancourt. “Most of my clients report feeling better and having more energy before any changes [happen] on the scale or in their clothes.” 

Can Dieting Impact Your Energy Levels?

Dieting, especially crash dieting, can also leave you feeling exhausted. “When someone loses a lot of weight, their body adjusts by reducing energy expenditure in order to try to regain the weight,” says Erogul. 

Overly restrictive diets can slow metabolism to a crawl, and your muscles will use as few calories as possible to function, according to the Ohio State Wexner Medical Center. “These adjustments can temporarily make some people feel they have less energy. Yet in the balance, the weight loss is good for you, and you will feel better,” says Erogul. Lose weight slowly to avoid the energy dips that come with overly restrictive diets. 

Here are some other things you can do to increase your energy, whether or not you’re currently losing weight.

Eat an energizing diet

According to the Academy of Nutrition and Dietetics, the best way to increase energy is to follow an eating plan that includes lots of whole grains, lean protein, fiber-rich fruits and vegetables, fat-free or low-fat dairy, and a small amount of healthy fat. On the other hand, diets high in sugars and saturated fats (like ultra-processed foods) wreck sleep quality and leave people feeling drained, according to research published in the journal Obesity.

Exercise regularly

You already know that exercise can be key to achieving and maintaining a healthy weight. It’s also useful for combating fatigue. One recent meta-analysis of 81 studies concluded that “moderate intensity exercise interventions of at least six weeks are on average beneficial for fatigue, energy, and vitality in healthy individuals and in those with chronic health conditions.” 

Lose Weight, Gain Energy

Whatever motivates your weight loss journey, you’ll likely gain more than improved bloodwork and a smaller pants size. As long as you avoid crash diets and overly restrictive plans, you can start feeling more energetic in the short term and long term alike. So on top of all the other benefits that come with weight loss, you’re likely to get an energy boost that helps you do more of the things you love. 
 

Editorial Resources and Fact-Checking

• Azzolino D et al. Nutritional Status as a Mediator of Fatigue and Its Underlying Mechanisms in Older People. Nutrients. February 10, 2020. 
• Sleep and Sleep Disorders. Centers for Disease Control and Prevention. September 7, 2022. 
• Silano M et al. Sleep Deprivation: Effects on Weight Loss and Weight Loss Maintenance. Nutrients. April 8, 2022.
• Sleep Apnea: Causes and Risk Factors. National Heart, Lung, and Blood Institute. March 24, 2022.
• Obesity. Cleveland Clinic. June 13, 2022. 
• Khonsari N et al. Association of Normal Weight Obesity Phenotype With Inflammatory Markers: A Systematic Review and Meta-Analysis. Frontiers in Immunology. February 26, 2023.
• All About Inflammation. Harvard Health Publishing - Harvard Medical School. June 15, 2020.
• Prediabetes Trends Among U.S. Adults. U.S. Pharmacist. November 18, 2022.
• Prediabetes. Mayo Clinic. November 11, 2023.
• Blasco B et al. Obesity and Depression: Its Prevalence and Influence as a Prognostic Factor: A Systematic Review. Psychiatry Investigation. August 12, 2020. 
• Depression. National Institute of Mental Health. September 2023.
• Bianchi VE. Weight Loss Is a Critical Factor to Reduce Inflammation. Clinical Nutrition Espen. August 18, 2018.
• How to Lose Weight Without Slowing Metabolism. Ohio State Wexner Medical Center. January 8, 2018. 
• Eating to Boost Energy. Academy of Nutrition and Dietetics. July 17, 2020.
• Brandão L et al. Exposure to a More Unhealthy Diet Impacts Sleep Microstructure During Normal Sleep and Recovery Sleep: A Randomized Trial. Obesity. May 28, 2023.
• Wender CLA et al. The Effect of Chronic Exercise on Energy and Fatigue States: A Systematic Review and Meta-Analysis of Randomized Trials. Frontiers in Psychology. June 3, 2022.