28th May 2024

What to eat while using weight loss medications

Weight loss medications are fast becoming a popular option for combating obesity. These GLP-1 agonist drugs are designed to slow digestion and suppress your appetite to aid in a rapid weight loss journey.

To learn more about weight loss medications, and to get a 1-day meal plan complete with delicious, healthy recipes, sign up to this free email series where Dr Michael Mosley and a trusted panel of health and medical experts share their insights. But to get you started, here’s an overview of what you should be eating if you’re considering using weight loss drugs.

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How weight loss medications impact your diet

Due to weight loss medications suppressing your appetite, the intention is that people using these drugs eat smaller portions, but this doesn’t often result in better food choices.

It also must be noted that once you stop taking the medications, your appetite returns to normal and it’s therefore common to regain the weight you lose. Plus, unless your nutrition and lifestyle supports muscle maintenance, it’s common for weight loss drugs to reduce your lean muscle mass, which is critical for maintaining a healthy metabolism and ageing.1

What to eat if you are using weight loss medications

When on weight loss medications, you can’t go too far wrong if you eat a Mediterranean-style diet. It’s low in carbs, and high in protein, fibre and healthy fats and it’s been shown to promote weight loss, maintain muscle mass and keep you properly nourished.

The two main nutrients you need to prioritise when on weight loss medications are protein and fibre:

  • Protein: If you don’t eat enough protein (at least 60g per day) when on weight loss medications, your body will scavenge protein from your muscles, resulting in loss of lean muscle mass. See here to find out how to eat more protein.
  • Fibre: We recommend eating 30g of dietary fibre every day to keep you full and keep your gut microbiome happy and healthy. Fibre is crucial to maintain a functioning digestive tract to mitigate any unwanted side effects like constipation or diarrhoea.

“The generous amount of protein we pack into each day is critical for supporting your metabolism and maintaining muscle mass, while fibre will keep your gut happy. You’ll see each Programme recipe uses foods you can easily find at a supermarket, with lots of natural proteins and vegetables to also provide your body with good sources of micronutrients.” – Gabi, The Fast 800 Nutritionist

Gabi’s five top tips

In addition to advising a high-protein and high-fibre diet, our nutritionist, Gabi, shares her five top tips on what to eat if you’re on weight loss drugs:

  1. Consume a Mediterranean diet for maximum variety – it focuses on adequate protein, healthy fats and lots of veg to keep you fueled well while using GLP-1 agonists.
  2. Skip the ultra-processed foods – these foods may be convenient but given your portion sizes are generally much smaller it’s best to reach for whole foods that are nutrient dense for maximum ‘bang-for-your-buck.’
  3. Ditch the sugar, have fruit instead – when using GLP-1 agonists, it’s best to avoid any foods that can cause rapid blood glucose spikes as this may reduce the medication’s effectiveness. If you’re wanting something sweet, choose low-sugar fruit such as berries, apples or pears which are full of fibre and nutrients.
  4. Incorporate mindful eating – By sitting to eat slowly and mindfully (i.e. not in front of the TV) you’re more likely to taste and enjoy your food.2 You’re also less likely to overeat which can cause strong feelings of discomfort and nausea for some using the medications.
  5. Aim to have dinner 3 hours before bed – this helps digestion and can improve sleep quality.3 This practice also reduces the likelihood of experiencing acid reflux after eating, which is common when lying down too soon after eating, particularly if using GLP-1 agonists.

How The Fast 800 can help

The Fast 800 is here to help make your weight loss journey as manageable and enjoyable as possible, with delicious recipes to inspire you, plans to guide you, exercise videos to energise you and a community to motivate you.

Our in-house nutritionists have designed plans that support rapid weight loss, whether you’re taking GLP-1 agonists or not, to help guide you through a learning experience you can take with you for life.

Whether you choose to take a medication route when it comes to your weight loss, or decide to tackle your health through diet and exercise alone, we always recommend prioritising quality rather than quantity when it comes to calories; it’s just a bonus that we make it all taste so good!

Start your 7-day free trial of our Programme today to see how it can support your weight loss journey, and sign up to our free email series to learn more about weight loss medications from the experts themselves and receive a complimentary 1-day meal plan to get you started!


McPherron AC, Guo T, Bond ND, Gavrilova O. Increasing muscle mass to improve metabolism. Adipocyte. 2013 Apr 1;2(2):92-8. doi: 10.4161/adip.22500. PMID: 23805405; PMCID: PMC3661116.

Chung N, Bin YS, Cistulli PA, Chow CM. Does the Proximity of Meals to Bedtime Influence the Sleep of Young Adults? A Cross-Sectional Survey of University Students. Int J Environ Res Public Health. 2020 Apr 14;17(8):2677. doi: 10.3390/ijerph17082677. PMID: 32295235; PMCID: PMC7215804.

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