Experts Reveal the Most Important Macronutrient for Weight Loss—and It’s Not Carbohydrates


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One of the schemes that unfolded in the original Mean Girls was new girl Cady Heron’s attempts to sabotage the uber-popular Regina George by feeding her lies about nutrition. That element of their feud led to some of the 2004 movie’s most memorable quotes. 

There was the nearly Shakespearean inquiry about the essential quality of a common food: “Is butter a carb?” And, of course, who could forget the brutal rebuke Regina issued after another friend suggested they go on a fun outing to a big fast-food chain: “I can’t go to Taco Bell, I’m on an all-carb diet. God, Karen, you’re so stupid!” 

These scenes reflected common attitudes about dieting: Regina was dumb, the movie implied, for not realizing that Cady’s suggestion to try “an all-carb diet” would obviously make her gain weight, not “lose three pounds” like she hoped to do. 

But how much do carbs really affect our bodies? A new study attempts to shed light on that. 

The research, conducted by the Human Research Committees of Brigham and Women’s Hospital and the Harvard T.H. Chan School of Public Health, used data from three large ongoing studies to evaluate the effects of low-carbohydrate diets on weight loss and management. 

Researchers concluded that protein intake ultimately mattered more. In their findings, people who consumed low-carb diets (LCDs) with a heavy focus on animal protein gained more weight over time than those who followed low-carb diets with an emphasis on plant-based proteins.

But however tempting it might be to toss out the chicken breasts in your freezer after reading that, you might want to exercise some caution when it comes to applying the study’s conclusions to your own life. 

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Craig Primack, MD, FACP, FAAP, FOMA, a physician specializing in obesity medicine, noted that the study has some important limitations. 

For starters, it measured changes in self-reported body weight over four-year intervals, rather than weighing respondents in a lab or instituting a rigorous method for tracking their actual food intake. 

“It’s really hard to determine what people are doing when you only ask them something every four years,” Dr. Primack, Senior Vice President of Weight Management at Hims & Hers, says. “If I asked you to recall your diet from even a month ago, like, ‘What did you eat over a given week?’ You’d be like, ‘A month ago—what date was that?’”

Tiffani Bachus, RDN, a dietitian and certified personal trainer, co-founded the wellness resource U Rock Girl with fellow RDN Erin Macdonald. The two dietitians share Dr. Primack’s concern about the methodology. Food frequency questionnaires like the one used in the study are susceptible to inaccuracies, she noted in an email. And despite its large sample size—a total of 123,332 respondents—the grouping of participants also isn’t as straightforward as it might seem. 

The study claims to evaluate five distinct kinds of low-carb diets: a “total LCD” focused on overall lower carb intake; an “animal-based LCD” focused on animal-sourced protein and fat; a “healthy LCD” focused on less refined carbs, more plant protein and healthy fat; and an “unhealthy LCD” focused on less healthy carbs, more animal protein and unhealthy fat. 

Bachus points out that the researchers lumped all animal protein in with their “unhealthy LCD” group, not just processed animal proteins. That makes the data harder to parse. We don’t know if those respondents were actually consuming healthy animal proteins, meaning any weight gain measured in the group can’t be meaningfully attributed to their animal protein intake.

As a general rule, experts agree, blanket statements about diets usually aren’t the answer. 

But protein does have a uniquely important role in our diets—including weight loss and management.

“Protein, which is made up of amino acids, are the building block and repair mechanism for every tissue in the body—muscle, bone, cells, digestive system,” Bachus explains. “Protein levels in the body, often regarded as lean mass, are directly correlated with metabolism. The higher the lean mass, the higher the metabolism.” 

Consuming a variety of protein sources throughout the day is one of the easiest ways to maximize these benefits. Some of the best sources of protein, Bachus notes, include a mix of animal and plant-based foods: organic poultry, pasture-raised eggs, wild-caught fish, raw nuts and seeds, organic soy and grass-fed/finished beef. 

The crucial role protein plays in building muscle also helps explain why just measuring weight loss isn’t an ideal way to evaluate the impact of diet on our health. 

As Dr. Primack notes, the new study doesn’t account for the fact that the total average weight loss of its “healthy LCD” group could very well be loss of muscle. And, of course, any diet that revolves heavily around restriction simply isn’t healthy—or even viable—for most people.


Our bodies need many different kinds of nutrients, which diets such as keto make harder to attain. Completely restricting specific foods, especially palatable ones like refined carbohydrates or fats, just isn’t a sustainable way of approaching diets. 

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Jessica Yu, Ph.D., a clinical psychologist and Sr. Director of Patient Experience at Hims & Hers, explains that this psychological pressure makes it more likely for people to have a hard time sticking to their rigid diets. And even if they do adhere to the diet for a set time, or lose the desired weight, people who are prone to all-or-nothing thinking tend to experience worse mental health outcomes. 

“If you restrict the types of foods that you eat, it may build up physical hunger, but it also builds up psychological hunger,” Dr. Yu says. “You start to crave the things that you used to enjoy without limitation.” 

Dr. Yu added that the most sustainable approach to weight loss is thinking flexibly about diets, regimens and what your unique body needs to succeed. That could mean working with a dietitian or consulting with a physician if you’ve spent considerable time struggling to lose significant amounts of weight. 

Whatever your plan, it’ll need to work for your lifestyle in the long-term. That’ll likely require changing your approach to both diet and exercise. Or, to put it a little more bluntly, odds are pretty high that you won’t achieve your goals by jumping on the latest iterations of fad diets.

As Dr. Yu explains, “I always encourage people, as you’re hearing about diets that may be popular, look at the diets and carefully do your research, but make sure to also understand your own behavior, history and preferences to decide what is the right diet for you.”

This article originally appeared on and was syndicated by

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Weight Loss Medications: Are They Actually Effective?

Weight Loss Medications: Are They Actually Effective?

It’s common knowledge that managing your weight keeps you healthy now and as you get older. In fact, obesity contributes to several health conditions, including heart disease, stroke, type 2 diabetes and certain types of cancer.

Not only was the prevalence of obesity in U.S. adults nearly 42 percent in 2017, but the estimated medical costs for adults with obesity were almost $2,000 more each year than for adults who do not have obesity .

Those who have a body mass index (BMI, or the measurement of fat based on height and weight) between 25 and 30 are considered overweight, while those with a BMI over 30 are considered to have obesity.

You’ve probably heard of a few weight loss medications, or at least their brand names, like Ozempic® and Wegovy®. However, there are several other prescription drugs available that are approved by the U.S. Food and Drug Administration (FDA) and frequently prescribed off-label for weight loss.

Healthcare providers may prescribe these medications to someone who has obesity or is overweight with a weight-related health problem like high blood pressure, high cholesterol or diabetes.


You’re probably familiar with one of semaglutide’s brand names, Ozempic — other brand names for this drug include Wegovy and Rybelsus®.

Ozempic is approved by the FDA to treat type 2 diabetes and may be prescribed off-label for weight loss, in combination with lifestyle changes like diet and exercise or with other diabetes medications like insulin or metformin.

Wegovy, meanwhile, is a prescription medication approved for use for weight loss in people who have obesity or who are overweight.

Ozempic and Wegovy are in a class of medication called GLP-1 receptor agonists, which mimic the hormone glucagon-like peptide-1 and target areas of the brain that regulate appetite.

Ozempic was approved by the FDA in 2017, while Wegovy was granted approval to pharmaceutical company Novo Nordisk more recently, in 2021.


Although only approved by the FDA to treat diabetes, metformin is often used off-label for weight loss, as well as gestational diabetes (a type of diabetes that develops during pregnancy) and polycystic ovary syndrome (PCOS).

It isn’t exactly clear how metformin helps people lose weight, but researchers think the drug works as an appetite suppressant. Similarly to Ozempic, metformin may increase how much GLP-1 hormone your body makes. This can send a signal to your brain that you’re full, which means you eat fewer calories.

Read our blog to learn about Ozempic vs. Metformin for weight loss.

(Related: Metformin For Weight Loss: Does It Work?)

Tatsiana Niamera/istockphoto

If you’ve dealt with depression or looked into medication to quit smoking, bupropion may sound familiar to you.

For weight loss, it can be combined with the drug naltrexone, which is used to treat alcohol and drug dependence, to curb your hunger or make you feel fuller sooner. Together, these medications work on two areas of the brain, the hunger center and the reward system, to reduce appetite and help control cravings.

Along with a reduced calorie diet and exercise plan, naltrexone-bupropion can also help keep excess weight off.


Phentermine-topiramate is actually two separate medications that are combined in Qsymia, but are offered separately in other applications. 

While phentermine is considered an anorectic and topiramate is an anticonvulsant, both help with appetite suppression.

Topiramate offers the added benefit of helping you feel fuller longer after you eat.

When used specifically with a healthy exercise regimen and a reduced calorie diet, these medications — either together or separately — have been shown to help people lose weight and keep it off.


Orlistat, which belongs to a class of medications known as lipase inhibitors, reduces the amount of fat your body absorbs from the food you eat.

Orlistat is used for weight loss in conjunction with exercise and a reduced-calorie diet, as well as after weight loss to help people keep from gaining back that weight.

While the brand name Xenical requires a prescription, another brand called Alli is available in a lower dosage without one.


Like Ozempic and Wegovy, liraglutide is an injected weight loss medication. It works as a GLP-1 receptor agonist to suppress appetite, similarly to semaglutide.

Also available under the brand name Victoza at a lower dose, this drug is FDA-approved to treat type 2 diabetes.

(Related: Weight Loss Injections: Are They Safe?)


These weight loss drugs are all available with a prescription from a healthcare professional, but how effective are they really?

  • One study found that when people without diabetes took a weekly semaglutide injection they had a higher average weight loss — almost a 15 percent average decrease in weight — than people who took a placebo.

  • Metformin has also demonstrated clinically significant weight loss. A 2020 meta-analysis of 21 trials testing metformin found the drug had a modest impact on lowering BMI, especially for those who are considered to have obesity.

  • smaller study on metformin also found that the average amount of weight lost in 154 patients was between 5.6 and 7 kgs (that’s roughly between 13 and 15 pounds).

It’s also worth mentioning cost here — if you can’t afford the drug you need to take, it’s effectiveness essentially drops to zero percent. That said, there’s some wide price disparity between weight loss drugs. 

For instance, injectibals like Ozempic and Wegovy are generally more expensive than orals like metformin — namely because metformin is a generic medication that’s been around for decades, and Ozempic and Wegovy are newer. 

Liudmila Chernetska/istockphoto

Because everyone’s weight loss journey is different, weight loss medications may work slowly for some people and faster for others.

How long you need to take a weight loss prescription drug depends on various factors such as what side effects you experience, how much weight you need to lose, whether the drug helps keep the weight off and more.

Generally, as found in the studies noted above and clinical trials, weight loss will occur within the first few months of using the medication.

Sometimes your health care professional may recommend long-term use of the medication, while other people may be advised to stop the drug if they don’t lose a certain amount of weight after 12 weeks.

If you’re taking a weight loss medication, your healthcare provider will likely suggest that you also increase your physical activity and make healthy lifestyle changes like eating lots of protein and fiber and getting enough sleep. These medications are the most effective when combined with healthy habits.

Jorge Elizaquibel/istockphoto

Just like any medication, weight loss drugs also come with the possibility of side effects.

When it comes to injectibal drugs like Ozempic and Wegovy, there are some broad side effects that apply to all injectibals — like swelling, redness or other discomfort at the injection site — but generally, the side effects profiles of these drugs are similar regardless of delivery method.

The most common side effects of many of these weight loss medications include:

  • Stomach pain or constipation

  • Diarrhea

  • Nausea

  • Vomiting

Some, like liraglutide and naltrexone-bupropion, may cause an increased heart rate or headaches.

Liraglutide and semaglutide may also increase the risk of pancreatitis (swelling of the pancreas). You may also have a higher risk of developing tumors or thyroid cancer when using liraglutide or semaglutide, although these serious side effects are very rare.


There’s a good chance you’ve heard of weight loss medications like Ozempic or even Wegovy, but there’s also a good chance that the headlines and celebrity-focused articles didn’t answer all your questions. Here’s what you need to know about whether they’re effective.

  • There are several FDA-approved weight loss drugs, including semaglutide, orlistat, phentermine-topiramate, naltrexone-bupropion and liraglutide. Metformin is another common medication used off-label for weight management.

  • These drugs all work slightly differently, but many decrease your appetite and help you stick to a lower-calorie diet. Healthcare providers often recommend they be used alongside regular exercise and healthy habits to maximize sustained weight loss.

  • However, there are side effects such as nausea, vomiting, diarrhea and constipation and, for the injectibals, injection-side irritation, injury or discomfort. Often, these are mild and serious side effects rarely happen.

  • Cost is also worth considering. Injectibals like Ozempic and Wegovy can generally cost anywhere from $800 to $1,000 per prescription, where a generic like metformin can be had for a fraction of that — usually for under $100 a month.

There’s no one “best weight loss medication” — there’s only what’s best for your particular needs. If you’re curious about medication for weight loss, you can talk to your healthcare provider for medical advice and to explore your options. And if you’re interested in other weight loss treatments online, we can help. 

This article originally appeared on and was syndicated by



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