GLP-1 receptor agonists, such as Ozempic, have revolutionized weight loss by helping individuals manage appetite and blood sugar levels. However, many people mistakenly believe eating as little as possible will enhance their results. Lakes Regional Healthcare (LRH) Registered Dietitian Nutritionist Beth Samuelson warns that under-eating on these medications can lead to health concerns. While GLP-1s significantly reduce hunger, your body still requires essential nutrients to function properly. Not consuming at least 60-75% of your maintenance calories can result in:
- Muscle Loss
A calorie deficit is necessary for weight loss, but if you eat too little, your body will break down muscle for energy—even if you consume adequate protein. Losing muscle mass lowers metabolism and makes it harder to keep the weight off long term.
- Slower Metabolism & Organ Dysfunction
According to Samuelson, after just five days of extreme calorie restriction, your metabolism slows down, and key organs—like your heart and liver—become less efficient. Additionally, your gut’s ability to move contents through your digestive system decreases, which can lead to bloating, constipation, and discomfort.
- Brain Fog and Lack of Focus
Your brain consumes about 20% of your daily calories and prefers glucose as its primary fuel source. Without enough carbohydrates, you may struggle with concentration, memory issues, and overall mental fatigue.
- Low Energy and Increased Risk of Injury
Exercise is an essential component of a healthy weight loss journey, but undereating leads to fatigue and poor performance. When your muscles lack energy, your workout form suffers, increasing the likelihood of injuries.
- Binge Eating and Digestive Discomfort
If you restrict calories too aggressively, your hunger hormones can spike later in the day, leading to overeating. Since GLP-1s slow digestion, large portions can cause severe discomfort, nausea, and even vomiting.
To avoid these pitfalls, Samuelson suggests following these practical nutrition strategies for sustainable weight loss while using GLP-1s:
- Eat 4-6 Times Per Day
Instead of skipping meals, space out your food intake every 2-3 hours to support digestion and maintain energy levels. This prevents nausea and excessive fullness while ensuring you get adequate nutrients.
- Keep Portions Small (2 Cups or Less)
Since GLP-1s slow stomach emptying, eating too much at once can cause discomfort. Stick to smaller, frequent meals to optimize digestion and prevent nausea.
- Choose Soft and Liquid Foods When Appetite is Low
If you struggle to eat, opt for soft or liquid-based meals, such as:
- Smoothies
- Protein shakes
- Soups
- Yogurt
- Cottage cheese
These options provide essential nutrients while being easier to digest.
- Eat Enough Protein (15-30g Per Meal)
Protein is essential for maintaining muscle mass, but it must be consumed consistently throughout the day. Eating too little protein can lead to muscle loss, while too much at once may cause nausea.
Good protein sources include:
- Lean meats (chicken, turkey, fish)
- Eggs
- Greek yogurt
- Low-fat cottage cheese
- Plant-based proteins (tofu, tempeh, lentils)
- Keep Carbohydrates Above 100g Per Day
Carbohydrates are necessary for fat metabolism and brain function. Without enough, your energy levels and mental clarity may suffer.
Healthy carbohydrate sources include:
- Whole grains (quinoa, brown rice, whole wheat bread)
- Fruits
- Vegetables
- Legumes
- Limit High-Fat Foods
Fat takes longer to digest, which can cause discomfort when using GLP-1s. Avoid heavy, greasy foods such as:
- Fried foods
- Butter-heavy dishes
- Fatty cuts of meat (ribeye, bacon)
- Large portions of cheese
Instead, Samuelson advises choosing healthy fats in moderation, like avocado, nuts, and olive oil.
- Prioritize Whole, Nutrient-Dense Foods
GLP-1s provide a unique opportunity to reset eating habits. Instead of processed foods, focus on:
- Lean proteins
- Whole grains
- Low-fat dairy
- Fruits & vegetables
This approach supports both weight loss and long-term health.
While GLP-1s help with weight loss, exercise is essential for preserving muscle and boosting metabolism. Samuelson encourages the following:
- Incorporate Resistance Training 3-4 Times Per Week
Strength training—whether using weights or bodyweight exercises—helps maintain muscle mass and prevents metabolic slowdown.
- Move Daily
Walking, yoga, or light cardio can improve digestion and overall well-being while on GLP-1s.
GLP-1 medications can be an effective tool for weight loss, but success depends on how well you nourish your body. Eating too little can lead to muscle loss, fatigue, and binge eating—ultimately sabotaging your progress.
By following balanced eating habits, prioritizing protein, consuming enough carbs, and incorporating exercise, you can lose weight in a healthy, sustainable way while maintaining muscle and energy levels.
