Everything you ever wanted to know about nutrition and training while using a GLP-1

GLP-1 receptor agonists, exercise and nutrition

GLP-1, or glucagon-like peptide-1, is a hormone produced in the intestines that plays a significant role in glucose metabolism and appetite regulation. It is released in response to food intake and has several key functions including:

• increasing insulin sensitivity,
• reducing blood sugar levels,
• slows gastric emptying and
• reducing appetite.

GLP-1 receptor agonists are a class of medications that mimic the action of GLP-1 and are primarily used in the treatment of type 2 diabetes. Research is also examining the efficacy of GLP-1 receptor agonists among heart failure patients and women with polycycstic ovary syndrome (PCOS). Examples of these medications available include liraglutide, semaglutide and dulaglutide.

GLP-1 receptor agonists are also used to support weight loss in individuals with obesity. Increasingly GLP-1 receptor agonists are being used by individuals without any chronic health concerns or obesity to support weight reduction.

The use of GLP-1 receptor agonists in otherwise healthy individuals who are exercising regularly has not been well researched and has possible implications for performance outcomes, recovery and long term health.

Possible risks or concerns utilising GLP-1 agonists for healthy women undertaking regular exercise training (and/or racing):

• Hypoglycaemia or a drop in blood glucose causing symptoms such as dizziness, fatigue, confusion, or irritability.

• GLP-1 receptor agonists lower blood glucose in a glucose-dependent manner—i.e., the higher your blood glucose gets, the more effective the medication is at lowering it.
• GLP-1 agonists also suppress the liver from releasing additional glucose into the bloodstream; the liver often serves as a crucial energy source during strenuous exercise.
• Glucose is the simplest source of energy during exercise, and as the intensity and duration increase, so too does our body’s demand for glucose. While GLP-1 receptor agonists help regulate blood sugar levels, prolonged or intense exercise can lead to a significant drop in glucose levels, particularly if carbohydrate intake is insufficient.

• Gastric/gut distress.

• GLP-1 receptor agonists slow gastric emptying, meaning they slow the rate at which we digest food. While this helps keep us feeling fuller for longer, it can lead to discomfort if food is not fully digested before exercise.
• Athletes can experience nausea, bloating or abdominal cramps, which can interfere with training or racing performance. Timing meals and the administration of GLP-1 agonists around workouts is essential to minimize these effects.

• Reduced recovery.

• Effective recovery from training sessions relies on adequate nutrient intake and absorption. Slower gastric emptying caused by GLP-1 receptor agonists can delay the absorption of carbohydrates and proteins needed for muscle repair and glycogen replenishment.
• This may lead to longer recovery times and could affect performance in subsequent training sessions or competitions.

• Impact on appetite regulation.

• While GLP-1 receptor agonists are effective at reducing appetite, this can be a double-edged sword for athletes who require increased caloric intake to support their training demands.
• The appetite-suppressing effects might lead to unintentional calorie deficits, particularly if not monitored closely, which can hinder performance and recovery.
• Long term this could continue to further hormonal disruptions and development of energy deficit conditions.

If you're considering using GLP-1 receptor agonists or are already using them while training, keep these points in mind:

1. Nutrition Matters:
• Are you eating a diet rich in whole, nutrient-dense foods? Focus on real foods that nourish your gut and support overall health.
2. Strength Training:
• Are you engaging in regular strength training? Building muscle quality and strength can enhance your resting metabolism, helping you maintain energy levels support positive body composition changes.
3. Prioritise Sleep:
• Are you making quality sleep a priority? Restful sleep is essential for recovery, hormone balance, and overall performance.
4. Hydration:
• Are you staying well-hydrated? Proper hydration is crucial for optimal performance and can help mitigate some side effects of GLP-1 receptor agonists.
5. Monitor Energy Levels:
• Are you paying attention to your energy levels during workouts? If you notice significant fatigue or dizziness, consider adjusting your nutrition or workout intensity.
6. Consult Professionals:
• We are all unique. An approach that works for someone may not work for you. Professional guidance can help tailor your nutrition and training plan to suit your specific needs and goals.
7. Listen to Your Body:
• Are you tuning into your body's signals? If you're feeling overly fatigued, experiencing digestive issues, or struggling with performance, it may be time to reassess your approach.

Fueling Strategies Around Training

Before Exercise

• Consume a balanced meal with both carbohydrates and protein 1-2 hours before exercising. However, avoid heavy or large meals due to the slower gastric emptying effects of the medication.
• Follow usual pre-exercise fueling guidelines, including hydration strategies based on the duration and intensity of your session.
• Make sure you allow enough time to digest the meal and avoid high quantities of simple carbohydrates – you do want to mitigate any possible gut distress and blood glucose spikes that could trigger a quick reduction in blood glucose levels.  If you do not have enough time to digest a full meal, small bites will suffice– you need some blood glucose available to support optimal training and recovery.

During Exercise

• For sessions lasting longer than 60 minutes, have quick-digesting simple carbohydrates on hand and consume them at regular intervals (5-12g every 10 minutes). Smaller, more frequent intakes help minimise spikes in blood glucose.
• Adhere to standard hydration guidelines, ensuring that you include electrolytes for sessions longer than 60 minutes (or 30 minutes in particularly hot or humid conditions).

After Exercise

• Note that you may not feel hungry at all, or you may feel very hungry!
• Ensure you consume a meal or drink with a 3:1 carbohydrate-to-protein ratio within 30 minutes of completing your session.
• Within 90 minutes of finishing, have a nutrient-dense meal containing high fibre, complex carbohydrates including protein, and healthy fats.
• Continue to drink water and prioritize hydration for the next 2-4 hours, depending on the intensity, duration and environment of your session.