How long does it take to notice weight loss? An obesity medicine specialist explains

If you’re starting a weight-loss plan, it’s only natural to wonder: How long will this take? When should I notice a change? How do I know if it’s working? 

We asked Dr. Rekha Kumar, a board-certified obesity medicine physician and the head of medical affairs at Found, to weigh in. 

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Q: Dr. Kumar, how long does it take to notice weight loss?

A: The initial stages of weight loss may be noticeable as soon as a few weeks for some people. But for most, it might take one to three months to notice a difference.

If you’re taking prescription weight-loss medication, it’s also worth noting that many weight-loss drugs have a ramp-up period where you start on a small dose and gradually increase the dose to give your body time to adjust to the medication and minimize side effects. While some people lose weight even on smaller doses, for others it can take three months or more to work up to their most effective dosage.

Q: At the most basic level, what needs to happen in the body for weight loss?

A: In order for weight loss to occur, there has to be an energy or calorie deficit over time, so the number of calories out needs to be greater than the number of calories in. 

It makes some sense that if you eat fewer calories than you burn, you’ll lose weight. But this is easier said than done. Initial weight loss in the first few days is often due to water loss because it takes time to lose body fat. And how long it takes to lose body fat really varies from person to person.

Q: What factors affect weight loss, and how quickly can someone lose weight?

A: Many environmental and biological factors can influence how fast or slow calories are burned and your overall rate of weight loss. These include:

• Your dietary calorie intake—the quality and quantity of calories you eat.
• Your physical activity level—how active you are and how frequently you exercise.
• The amount of quality sleep you get each night.
• Your starting weight and general health.
• Your age, hormone levels, and menopausal status.
• Your biological sex.
• Medications you’re taking.
• Other medical conditions you may have.
• Your genetics.

Q: What are the key stages of weight loss? Is there typically a fast and a slow stage?

A: In the first few days, there might be water weight loss from certain diets like low-carbohydrate diets. Then, gradually, after days to weeks, stored fat begins to be burned. Some people with obesity may see a rapid weight loss of several pounds (usually water) in the first week and a weight loss of 1 to 2 pounds per week initially. Still, for others, weight loss may be more gradual.

Q: What are the first signs of losing weight? Is there a part of the body where you see weight loss first?

A: Where you notice your weight loss first can vary greatly. It depends on genetics, body composition, and even biological sex. For example, men tend to lose more weight around their waist than women. And women tend to lose more weight around their hips than men. Some might notice it in their thighs or arms first because of how their pants or shirt sleeves fit and feel. Often, each person experiences a different weight loss pattern.

Q: How much weight do you need to lose before you notice?

A: Some research suggests weight loss is generally noticeable when people have lost 5% to 10% of their body weight or reduced their body mass index (BMI) by 1 to 3 points. So, if you are of average height and currently weigh 250 pounds, it’s likely that you and those who see you regularly might notice a difference when you’ve lost 12.5 to 25 pounds. 

It’s important to remember that even modest weight loss can improve health. A 5% body weight loss can lower blood pressure, cholesterol, blood sugar levels, and the risk for some chronic diseases. And faster isn’t necessarily better: Less rapid weight loss has been associated with better overall body composition—less body fat around the organs, more lean muscle mass, and a better total body fat percentage.

Q: In the first months of a successful weight loss treatment plan, what should you expect to see if it’s working? 

A: You may notice clothes feeling loose or see the scale go down if you weigh yourself regularly. But there are other, less outwardly obvious or easily measured signs you might notice, such as:

• Feeling full faster and longer.
• Having fewer food cravings.
• Sleeping better.
• Feeling sharper and having more energy.
• Moving or breathing more easily when exercising or walking up stairs.

Q: How can you tell if you’re losing fat (vs muscle)?

A: You cannot tell exactly. Studies and clinical practice show that people who lose weight rapidly can also lose lean muscle mass, so it’s important that your diet plan includes enough protein and that your exercise plan incorporates strength training to avoid muscle loss as you’re losing weight. 

Body composition scales, while not entirely accurate, can also be helpful for some patients to get a general sense of their fat loss and muscle building. It can be encouraging to know things are happening beneath the surface when the total number on the scale seems stuck or moving more slowly than you’d like. 

But, even without a body composition scale, if you are getting enough protein and doing resistance training, you should be burning more fat than muscle. Also, your waist circumference should decrease as you burn fat and build muscle.

Q: Bottom line: What is a realistic timeline for weight loss?

A: For the initial phase, one to three months is a realistic time frame as your body adjusts to any medications and to the lifestyle changes you are making. Then, continued weight loss for six to 12 months if you adhere to your lifestyle changes, healthy habits, and calorie deficit.

Q: What’s the best way to get started?

A: Achieving sustainable weight loss on your own can be difficult. Not all plans are safe and sustainable for all people. And it’s easy to get frustrated if you aren’t achieving your weight loss goals as quickly as you’d hoped. So, I always recommend talking openly with an obesity medicine or weight care specialist, or another trusted health care provider, to determine a safe and sustainable approach for you. And it’s smart to choose a plan with ongoing monitoring and some built-in support. 

That’s really the hallmark of Found. We’ve built our clinic to support you as you navigate your healthy weight loss journey. Our MetabolicPrint™ process, designed by obesity medicine specialists, helps pinpoint your body’s unique characteristics and weight loss obstacles. This allows your Found clinician to design a personalized treatment with prescription medications when appropriate. (All prescriptions at Found are written at a provider’s discretion.) Our online community and app help patients stay on track and provide reassurance when frustration hits.

About Found

Found is among the largest medically-supported telehealth weight care platforms in the country, having served more than 250,000 members to date. To discover your MetabolicPrint™ and start your journey with Found, take our quiz. 

This content does not provide medical advice and does not substitute for a consultation with a doctor or health care provider.