Our Mission

What Does This Mean For Your Future Health?

Author: Dr. Stephen Chaney

Most people want to lose weight so they can get trimmer and healthier. I don’t know of anyone who wants to be leaner and less healthy. But if they are not getting the essential nutrients their body needs while they are losing weight, they may well end up both lean and unhealthy.

I don’t need to tell you that GLP-1 (glucagon-like peptide 1) drugs are all the rage. Total spending on GLP-1 drugs in the United States exceeded $71 billion in 2023, a 500% increase in just 5 years. There are 15 million Americans on GLP-1 drugs at any one time. And most of this increase has been driven by the weight-loss market.

GLP-1 drugs do work. They target the intestine and the brain, increasing satiety (feeling of fullness) and decreasing appetite.

However, like any other drug, they have side effects. The most frequent are:

• Nausea
• Vomiting
• Diarrhea
• Constipation
• Increased heart rate.
• Hypoglycemia
• Allergic reactions

In a previous issue of “Health Tips From the Professor” I discussed a serious side effect that is often overlooked, namely increased risk of depression, anxiety, and suicidal thoughts. My recommendations were:

• If you suffer from depression, anxiety, or suicidal thoughts, GLP-1 drugs may not be the best choice for you. At the very least you should discuss the risks and benefits with your doctor before using them.

• If you are using GLP-1 drugs and experience an increase in depression, anxiety, or suicidal tendencies, you should discontinue the drug immediately and report your side effects to your doctor.

Another question that has not been addressed previously is whether people using GLP-1 drugs are getting the essential nutrients their bodies need for optimal health. Today’s study (B Johnson et al, Frontiers in Nutrition, published online in April 2025) was designed to measure the nutritional adequacy of GLP-1 user’s diets.

How Was This Study Done? 

The investigators enrolled 69 people who had been using a GLP-1 drug for at least a month in their study using an online research platform through the University of Turin in Italy.

The characteristics of the study participants were:

• Weight:

• • 5% normal weight

• • 27% overweight

• • 18% Obese Class I

• • 20% Obese Class II

• • 30% Morbidly Obese

• Age = 49.6 ± 12.3

• Ethnicity:

• • 82% Caucasian

• • 6% Hispanic

• • 8% African American

• • 1% Asian

• • This is similar to the ethnic distribution of GLP-1 users in this region.

• Length of GLP-1 use:

• • 7% <3 months

• • 29% 4-6 months

• • 25% 7-12 months

• • 39% >1 year

The participants were trained on how to use an online dietary recall instrument and then recorded their dietary intake for 3 consecutive days.

Are GLP-1 Users Getting Enough Nutrients?

The results of the 3-day dietary recalls from the GLP-1 users were:

• Their diets were high in fat (39% of calories) and saturated fat (13%).

• Their diets were low in fruit, vegetables, grains, and dairy foods.

• Their diets were low in fiber (14 grams). This is half the recommended intake of fiber.

• Their diets were sufficient for B-vitamins, copper, phosphorous, selenium, and zinc.

• Their diets were deficient for calcium, iron, magnesium, potassium, choline, vitamin A, vitamin C, vitamin K, vitamin D, vitamin E, and fiber. For example:

• • 99% of participants were not getting enough Vitamins D and K from their diet.

• • 94% weren’t getting enough choline.

• • 90% weren’t getting enough magnesium.

• • 88% weren’t getting enough iron.

The study did not report the intake of omega-3 fats, but the participants were likely deficient in that as well.

The study participants averaged 0.8 gm/kg of protein, which is the recommended intake for sedentary adults who are not on a weight loss diet. However, 0.8 gm/kg of protein is not sufficient for maintaining muscle mass on weight loss diets, especially weight loss diets aided by GLP-1 drugs. Most experts recommend 1.2gm/kg to 1.6 gm/kg to prevent loss of muscle mass, with a few recommending as high as 2 gm/kg.

Most of the participants in this study did not meet the increased protein recommendations for weight loss.

• Only 43% consumed at least 1.2 gm/kg of protein.

• Only 10% consumed at least 1.6 gm/kg of protein.

• Only 5% consumed at least 2.0 gm/kg of protein.

The authors concluded, “Participants on a GLP-1 drug are not meeting the DRI [daily recommended intake] for several vital nutrients through their diet or the higher protein needs during weight loss. Patient-centered nutritional guidance is essential to optimize health outcomes and prevent unintended health consequences.

What Does This Mean For Your Future Health?

The results of this study are both appalling and expected. Weight loss diets often result in nutritional insufficiencies. However, GLP-1-aided weight loss is worse.

That’s because GLP-1 is a drug, not a diet plan. It’s dispensed like any other drug.

• Your doctor gives you a GLP-1 prescription. If you are lucky, they may give you a “one-size-fits-all” handout on how to lose weight while you are using it. For example, in this study:

• • Only 51% of participants received information from their doctor on how to manage side effects of GLP-1.

• • Only 20% were referred to a dietitian. The other 80% received no information on how to change their diet and lifestyle.

• When you pick up the drug from the pharmacy, you get a package insert listing the side effects but no information on how to change your diet.

The results were predictable:

From a medical point of view the results were a big success:

• The participants in the study reduced their caloric intake by 20%.

• Most of the participants in the study felt the GLP-1 drug was helping them lose weight.

But from a nutritional point of view the study raises a red flag. Most of the participants were not told to change their diet or lifestyle, and they didn’t. Their diet was still:

• High in total fat and saturated fat and probably low in healthy fats, although that was not assessed.

• Low in fruits, vegetables, grain, dairy, and fiber.

The typical American diet is bad enough as it is. But when you eat the same diet and decrease calories, the nutritional inadequacies of the American diet are magnified. That is why the diets of the GLP-1 users were deficient in fiber plus 10 essential vitamins and minerals and did not contain enough protein to prevent loss of muscle mass.

Most (52%) of the participants were planning to be on GLP-1 drugs for a short period of time – just long enough to reach their weight loss goals. But the reality is far different.

Studies show that when people lose weight on GLP-1 drugs without changing their diet and lifestyle, the weight comes roaring back as soon as they get off the drugs. The reality is that those people will need to stay on GLP-1 drugs for a lifetime if they want to keep the weight off.

That’s when the nutritional inadequacies shown in this study start to have real health consequences. For example,

• Long term inadequacies of calcium, magnesium, and vitamin D increase the risk of osteoporosis.

• Long term muscle loss due to inadequate protein intake leads to frailty and metabolic diseases as we age.

I could go on, but you get the point. GLP-1 drugs are not a panacea. Without diet and lifestyle change, they are just a temporary and expensive solution to weight loss.

The Bottom Line

A recent study looked at the nutritional intake of GLP-1 users. It found:

• Their diets were high in fat (39% of calories) and saturated fat (13%).

• Their diets were low in fruit, vegetables, grains, and dairy foods.They were deficient in fiber plus 10 essential vitamins and minerals.

 

• They were not getting enough protein to prevent the loss of muscle mass associated with GLP-1 use for weight loss.

The authors concluded, “Participants on a GLP-1 drug are not meeting the DRI [recommended intake] for several vital nutrients through their diet or the higher protein needs during weight loss. Patient-centered nutritional guidance is essential to optimize health outcomes and prevent unintended health consequences.

For details about the study and the health consequences of these nutrient deficiencies, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

______________________________________________________________________________

My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

_____________________________________________________________________

About The Author 

Dr. Chaney has a BS in Chemistry from Duke University and a PhD in Biochemistry from UCLA. He is Professor Emeritus from the University of North Carolina where he taught biochemistry and nutrition to medical and dental students for 40 years.

Dr. Chaney won numerous teaching awards at UNC, including the Academy of Educators “Excellence in Teaching Lifetime Achievement Award”.

Dr Chaney also ran an active cancer research program at UNC and published over 100 scientific articles and reviews in peer-reviewed scientific journals. In addition, he authored two chapters on nutrition in one of the leading biochemistry text books for medical students.

Since retiring from the University of North Carolina, he has been writing a weekly health blog called “Health Tips From the Professor”. He has also written two best-selling books, “Slaying the Food Myths” and “Slaying the Supplement Myths”. And most recently he has created an online lifestyle change course, “Create Your Personal Health Zone”. For more information visit https://chaneyhealth.com.

For the past 53 years Dr. Chaney and his wife Suzanne have been helping people improve their health holistically through a combination of good diet, exercise, weight control and appropriate supplementation.