Weight Loss 101: Is There a Safe and Effective Way to Lose Weight Long-Term?

Reviewed by Dr. Jonathan Bonnet, MD, MPH and Judy Singer, RD

Few of us are strangers to the often unattainable goals of weight loss: An estimated 45 million Americans go on a diet every year, spending over $30 billion dollars on programs, supplements, and “healthy” meal alternatives.

Despite frequent attempts to lose weight, experts believe that between 80-95% of dieters gain back the weight they worked hard to lose within one to five years. In some cases, they end up even heavier after dieting.

So why do we keep trying to lose weight?

Over the past thirty years, we’ve been bombarded with messaging on the direct correlation between increased weight and poorer health outcomes. What’s more, social pressures continue to emphasize the aesthetics of losing weight regardless of supposed health benefits. But emerging research suggests that the relationship between weight and health is more nuanced. What’s more, data shows that yo-yo dieting, over-exercising, and extreme weight loss can often be more dangerous to one’s health than simply remaining at a larger size.

Which leaves most of us wondering—do I really need to lose weight for my health, and if so, is there a safe and effective way to do it?

How do I determine what my optimal weight should be?

Until recently, the body-mass index (BMI) has been the accepted method for determining one’s “ideal weight.” As a calculation, BMI has two big advantages: simplicity and availability of data. By using one’s height and weight, BMI aims to offer an indicator of health.

BMI can be helpful on a population level, but it remains an unreliable measure of individula body fat, build or health and ignores current understanding of body composition.

(Importantly, the original data used to build the BMI included only white, Western European men, and as recently as 2011 the index fails to accurately detect more than 50% of obesity cases in Black, white, and Hispanic women.)

Today, medical experts have recognized the failings of BMI as a health indicator and prefer to use other methods, like body-composition analysis (BCA), to determine a patient’s optimal weight.

Unlike the BMI, BCA techniques take the complexities of the human body into account, including body fat distribution, age, sex, genetics, lifestyle, health risks, and specific metabolic and functional traits (like energy expenditure, insulin sensitivity, muscle strength, and physical performance).

Using this approach, determining your healthy body weight isn’t about a specific value or range, but analyzing those values within their physical and functional contexts.

In other words, your optimal weight may be very different from the optimal weight for another person of similar height.

Common causes of weight gain

For many of us, body weight is a reflection of a unique set of genetic, behavioral, and environmental factors. Gaining weight could be a symptom of hormonal dysfunction as much as it could be a result of living in a food desert, lack of sleep, starting a new medication, or recovering from an eating disorder (ED).

Emotional health can have an impact on weight, too. Stress, anxiety, and depression can cause weight gain in some people.

Specifically, chronic stress can increase food cravings, increase blood pressure, worsen glucose metabolism, and impair our ability to make healthy choices.

With so many potential causes, it can be difficult to identify the root cause of weight gain, but talking with your Forfend provider can help determine what additional interventions or testing may be helpful.

Do I need to get lab tests?

Recent, unexpected, or dramatic weight gain or loss can be worrying. But working with a provider can help you determine whether additional testing is necessary to identify the root cause.

Depending on any additional symptoms you may be experiencing along with your weight history, past medical history, family history, food intake, activity level, your doctor may recommend one or more of the following lab tests:

  • Complete blood count (CBC)

  • Electrolytes

  • Liver function

  • Kidney function

  • Lipid profile (aka Cholesterol Panel)

  • Thyroid tests

  • Hemoglobin A1c

  • Uric Acid

  • Vitamin D

How can I realistically lose weight?

A landmark study following 14 former participants on the extreme weight loss reality TV show, The Biggest Loser, found that following extreme weight loss, participants’ resting metabolic rate (the rate at which your body burns calories when at rest) significantly decreased.

As a result of the body’s effort to fight back against weight loss and defend its “set point,” many participants ended up regaining much if not all of the weight they had struggled to lose while on the TV show.

The study demonstrates how extreme weight loss can permanently alter or damage a person’s metabolism. One participant, who regained more than 100 pounds after filming, currently eats just 800 calories a day to maintain his current weight of 295 pounds.

Put simply: Losing weight is really hard, and in many cases, people inevitably gain the weight back as their body remains in a constant battle against their physiology and metabolism.

Given the historical data of people who gain weight back after dieting, losing weight in a healthy and sustainable way may seem unrealistic. Thankfully, research shows that long-term, sustainable weight loss is possible in some people when incorporating the following:

  • A modest goal of just 5-10% body weight loss

  • At least 150-300 minutes of moderate-intensity physical activity per week, or 75-150 minutes of vigorous-intensity aerobic physical activity per week

  • Behavior and lifestyle modifications

Which lifestyle changes actually improve weight loss?

We can’t change our biology or genetics. But there are some lifestyle changes that can help support healthy weight loss and weight loss maintenance.

Research has shown specific lifestyle changes to be more correlated with weight gain than others. Though these behaviors don’t necessarily cause weight gain, they can be markers for something else (like a sedentary lifestyle and poor nutrition).

Lifestyle factors independently associated with long-term weight gain include:

  • Eating potato chips, potatoes, sugar-sweetened beverages, unprocessed red meats, and processed meats, and processed foods in general

  • Alcohol use (which can increase our calorie intake, disrupt sleep, and increase poor food choices)

  • Sleeping less than 6 hours

  • Television watching

But lifestyle changes inversely associated with long-term weight gain include:

  • Eating vegetables, whole grains, fruits, nuts, and yogurt

  • Physical activity

  • Getting a sufficient amount of sleep to feel well-rested (typically between 7-9 hours for adults)

In summary, factors associated with a healthier weight include getting a good night’s sleep, eating nutritious meals, and moving regularly. Unsurprisingly, these behaviors can also help support long-lasting and sustainable weight loss.

Do I need weight loss medication?

When combined with nutritional changes, increases in physical activity, and behavioral therapies, some medications can help to treat disease, facilitate management of eating behaviors, and slow progression of weight gain and regain. In some cases, these medications can also help to improve the health and quality of life in people living with obesity and chronic diseases.

The biggest challenge with weight loss medications is that they generally have to be continued to maintain however much weight is lost. If not, nearly all of the weight can return whenever you stop taking the medication.

Not to mention, some medications can carry significant risks and side effects and may be less effective at promoting long-term weight maintenance.

One medication that research shows may be the most effective at supporting weight loss is semaglutide, a new weight loss, GLP-1 medication approved by the Food and Drug Administration (FDA). A recent study showed that treatment with semaglutide and lifestyle changes can help patients lose close to 15% of their body weight over 16 months. However, like all weight loss medications, any weight that is lost while on them is often regained when the medication is stopped.

Regardless of which medication you’re considering, it’s important to talk to your doctor about possible risks and contraindications to determine whether or not it’s right for you.

The bottom line

It’s natural for our bodies to change as our emotional, physiological, and environmental factors shift. Gaining weight isn’t necessarily a sign of disease or failure, and in many cases, a healthy and intuitive relationship with food and movement is enough to support our physical and emotional health in the long run.

For others, a comprehensive and sometimes medically-supervised approach to weight loss can be effective at making lifelong positive changes to their health. But keep in mind that to support long-lasting weight loss, behavior modifications are key.

Fad diets promising fast and drastic weight loss generally don’t work in the long run and can be dangerous in the short-term, with possible long-term ramifications on your physical and mental health.

Losing weight sustainably often involves supporting 5-10% body weight loss with achievable lifestyle and behavior modifications over a long period of time, including better sleep, a more nutritious diet, and regular exercise. If you’re ready to start making sustainable changes, book an appointment with Forfend and we’ll help you create a personalized plan.


Accuracy of current body mass index obesity classification for white, black and Hispanic reproductive-age women. (2011).

Brain GLP-1 and Insulin Sensitivity. (2016).

Changes in Diet and Lifestyle and Long-Term Weight Gain in Women and Men. (2011).

Did the American Medical Association make the correct decision classifying obesity as a disease? (2014).

Distance to Store, Food Prices, and Obesity in Urban Food Deserts. (2014).

Ideal body weight or BMI: so what’s it to be? (2016).

Long-term weight loss maintenance. (2005).

Obesity: Lifestyle Modification and Behavior Interventions. (2020).

Obesity algorithm. (2021).

Once-Weekly Semaglutide in Adults with Overweight or Obesity. (2021).

Persistent metabolic adaptation 6 years after The Biggest Loser competition. (2017).

The Bizarre and Racist History of the BMI. (2019).

Weight Management. (n.d.).

Yo-yo dieting may increase women’s heart disease risk. (2019).

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