Newswise — By Jaime Almandoz, M.D., Associate Professor of Internal Medicine in the Division of Endocrinology

Since anti-obesity medications such as semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound) have become more widely known and prescribed, they have been touted as game-changing treatments for chronic overweight and obesity.

Anti-obesity medications work by signaling the brain that we have eaten and the stomach is full, so patients feel satisfied with less food for longer, and cravings are diminished. These powerful mechanisms can result in an average of 15%-20% body weight loss, which can be lifechanging for many people.

But one common misconception about these medications is that they’re a magic bullet for better health, and it doesn’t necessarily matter what you eat when you’re taking them. Nothing could be further from the truth.

The average American diet is low-quality. It is high in ultra-processed, calorie-dense foods and is often deficient in fruits, vegetables, fiber, and essential nutrients. Eating less of a low-quality diet could increase the risk of unintended health outcomes, including loss of muscle mass, fatigue, and malnutrition.

Data from decades of successful weight management with bariatric surgery have shown that patients benefit from expert guidance on how to change what they eat long term. Before patients undergo bariatric surgery such as gastric bypass or gastric sleeve procedures, they have multiple visits with a registered dietitian to create a healthy eating plan for adequate nutrition after surgery. In addition, there are guidelines for patients who get bariatric surgery to take vitamin supplements and have their vitamin levels checked annually for the rest of their lives.

No such guidelines exist yet for anti-obesity medications, though patients now lose similar amounts of weight with these medications as they do with bariatric surgery.

Anti-obesity medications, which were initially developed to treat diabetes, are still relatively new in the weight loss world. Unfortunately, due to the high prevalence of obesity (over 40% of adults) and lack of obesity medicine-trained clinicians, people may be getting anti-obesity medications from providers with little or no training in obesity care.

Simply telling patients using these medications to eat less of what they are currently eating or to eliminate specific types of food such as carbohydrates can create ineffective cycles of restrictive dieting, poor nutrition, and gastrointestinal symptoms such as nausea, constipation, and diarrhea.

At UT Southwestern’s Weight Wellness Program, our obesity specialists help patients use anti-obesity medications to transform their health with personalized nutrition education and guidance. We guide patients toward sustainable and healthier eating plans.

Collaborating with experts in nutrition, endocrinology, and internal medicine from across the U.S., our team has created the first set of nutritional recommendations for safe, successful anti-obesity medication use. Our evidence-based review is designed to guide providers in helping patients get off to a healthy start with anti-obesity medications and achieve sustainable weight wellness based on their known health conditions, nutritional needs, and health goals.

6 nutritional building blocks for healthy eating

Successful weight loss starts with feeding the body a balanced, healthy diet. Understanding a patient’s baseline health conditions, activity level, cultural traditions, medications, and known nutritional deficits can reduce the risk of potential anti-obesity medication misadventures, such as not eating enough protein, which can lead to losing muscle mass and could increase the risk of fatigue, frailty, or falls.

Most people can safely get their six main nutritional building blocks by following some general daily dietary recommendations.

Fluids

Recommended daily intake: 2-3 liters

Where to get it:

  • Water
  • Low-calorie tea or coffee
  • Nutrient-dense low-fat milk or soy milk

Signs of deficiency:

  • Low blood pressure
  • Fast heartbeat
  • Dizziness

Considerations:

  • Limit sugar-sweetened beverages, caffeine, and alcohol
  • Very low-carb diets can increase dehydration risk

Energy

Recommended daily intake: 1,200-1,500 calories for women; 1,500-1,800 calories for men

Where to get it:

  • Vegetables
  • Fruits
  • Whole grains
  • Lean proteins
  • Low-fat dairy or dairy alternatives
  • Healthy fats

Signs of deficiency:

  • Loss of muscle mass
  • Decreased strength

Considerations: Goals for intake during weight loss should be personalized.

Fiber

Recommended daily intake: 21-25 grams for women; 30-38 grams for men

Where to get it:

  • Whole grains
  • Vegetables
  • Fruits
  • Beans
  • Peas
  • Lentils
  • Nuts and seeds

Signs of deficiency: Constipation

Considerations:

  • Plant-based foods are a great source of fiber.
  • Fiber supplements may benefit some patients.

Protein

Recommended daily intake: 60-75 grams (10%-35% of calories)

Where to get it:

  • Beans
  • Peas
  • Lentils
  • Nuts and seeds
  • Soy
  • Seafood
  • Lean meat
  • Poultry
  • Dairy
  • Eggs

Signs of deficiency:

  • Loss of lean body mass
  • Weakness
  • Fluid retention
  • Hair loss
  • Skin changes

Considerations: Meal-replacement products (15–25 grams of protein per serving) may benefit some patients

Carbohydrates

Recommended daily intake: 135-245 grams for 1,200-1,500 calorie diet

Where to get it:

  • Whole grains
  • Fruits
  • Vegetables
  • Nuts and seeds
  • Dairy foods and dairy alternatives

Signs of deficiency:

  • Dehydration
  • Fatigue
  • Halitosis (bad breath)

Considerations:

  • Low carb intake may restrict fruits, vegetables, and whole grains (key sources of fiber and nutrients).
  • Limit added sugars.

Fats

Recommended daily intake: 27-58 grams (20%-35% of calories)

Where to get it:

  • Nuts
  • Seeds
  • Avocados
  • Vegetable oils
  • Fatty fish
  • Seafood

Signs of deficiency:

  • Dry skin
  • Hair loss
  • Impaired wound healing

Considerations:

  • Limit saturated fat, palm oil, and coconut oil.
  • People who have trouble digesting food are at risk of essential fatband fat-soluble vitamin (A, D, E, and K) deficiency.
  • Eating high-fat meals can cause gastric distress.

Personalized eating plans can help

Dietary coaching on what foods to try and how to eat while taking these medications can help patients reduce the risk of medication-related gastrointestinal side effects, such as bloating, nausea, vomiting, diarrhea, and constipation. For example, if we know up front that a patient doesn’t eat enough dietary fiber, we may recommend a fiber supplement and extra hydration to help keep their digestive tract moving.

There is no dietary checklist that works for everyone. Each patient needs a personalized eating plan to meet their needs. However, people who take anti-obesity medications can follow a few basic recommendations to decrease the risk of gastrointestinal side effects:

  • Avoid fried and high-fat foods
  • Limit intake of carbonated drinks, alcohol, and spicy foods
  • Eat smaller meals and be aware of fullness cues

Know the risk factors for malnutrition

When we meet a new patient in the Weight Wellness Program, we spend about an hour talking through their health history and their goals. The patient also meets with a registered dietitian for about an hour. These conversations help us to get a more holistic view so that we can create individualized treatment and nutrition plans for each patient.

Most community health clinics and primary care physicians don’t have the time in their schedules or specific training in obesity care to go into this much nutrition detail with their patients. It is very important for patients who take anti-obesity medications to understand how to create a balanced diet that leads to both weight loss and better health. Simply eating less and skipping meals when taking anti-obesity medications can sometimes do more harm than good.

Consider talking with an obesity specialist or ask your primary care provider for a referral to a registered dietitian if you have any of these risk factors for malnutrition when taking an anti-obesity medication:

  • History of gastrointestinal procedures or bariatric surgery: Gastrointestinal procedures can alter nutrient absorption and may also increase the risk of gastrointestinal side effects from anti-obesity medications.
  • Advanced age: Older adults may have health issues that require special nutritional considerations to decrease the risk of muscle loss and frailty. Rapidly losing large amounts of weight may not be safe for older adults.
  • Chronic disease: Conditions such as kidney disease, diabetes, and cardiovascular disease may require specialized diets and adjustments in other medications (such as insulin, blood pressure and thyroid medications) while taking an anti-obesity medication and losing weight.
  • Unintended rapid weight loss: Rapid and unintended weight loss can indicate an underlying health condition or that the anti-obesity medication dose is too high.
  • Dental health issues: Gum disease or missing teeth can make chewing difficult and painful, resulting in low intake of nutrient and fiber-rich foods.

Nourishing the body instead of limiting food intake can maximize the effectiveness of anti-obesity medications to improve health and quality of life – beyond just decreasing the number on the scale.

As patients and providers incorporate anti-obesity medications into their long-term health plans, conversations should pivot away from the generalized, restrictive dietary recommendations of the past. Instead, creating a balanced, evidence-based eating plan that fuels weight loss and a healthy lifestyle will be the key to building sustainable solutions for patients.

Related reading: 

Weight-loss medications: The 5 most-asked questions

Why it’s so hard to keep excess weight off and how long-term treatment can help

Metabolic reset: Benefits of bariatric surgery beyond weight loss

Anti-obesity drugs are closing the gap between dieting and bariatric surgery

Obesity drugs help patients lose weight regained years after bariatric surgery

Nutrition know-how for patients taking anti-obesity medication

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