How many calories should I eat on Mounjaro? The simple formula

From getting out of bed on a cold morning to giving up your nightly doom scroll, many things in life are simple in theory, but not easy. Weight loss can certainly fall into that category — as anyone who has ever been on the receiving end of advice like "just burn more calories than you eat!" can attest.

For many, medications like Mounjaro can make the weight journey feel much more effortless. And in great news for those who loathe inspecting the numbers on food packaging, you don't necessarily even have to count calories for it to work. Many people find that they naturally eat less, without thinking much about food (or calories) at all.

That said, to get the most out of your treatment — and, actually, sustain your results — it can be helpful to have an idea of your numbers. Read on for your simple (and easy) guide to calculating how many calories you should consume on Mounjaro.

What is Mounjaro?

Mounjaro is the brand name for the weight loss medication, tirzepatide. Created as a diabetes medication, it's also prescribed for weight loss for those who are obese or overweight with related health issues. Mounjaro is administered weekly via subcutaneous injection (under the skin, in the abdomen, upper arms or thighs).

How does Mounjaro work?

Mounjaro works similarly to other weight loss medications like Ozempic — mimicking the naturally occurring hormone, GLP-1 (glucagon-like peptide-1) to stimulate the production of insulin in the pancreas [1]. This helps to regulate blood sugar and send messages to the brain that you are satiated. It also slows down the gastric emptying of the stomach, which also helps to keep you full for longer.

However, unlike Ozempic, Mounjaro has a dual agonist mechanism — in that it mimics the metabolic hormone GIP as well as GLP-1 [2]. Thanks to this 'twincretin' effect, Mounjaro has actually been found to be slightly more effective than other medications for weight loss. In one study, 81.8% of adults lost at least 5% of their body fat within a year taking Mounjaro, compared to 66.5% taking Ozempic [3].

How many calories should you eat on Mounjaro?

There's no one answer to the question 'how many calories should be on a Mounjaro diet plan?' The answer depends on your lifestyle, goals and other health factors. That said, some general considerations can help get you started on the right track.

General guidelines for calorie intake

In order to lose one kilo of fat, you need to be in a calorie deficit of around 7700 calories [4]. So, to lose half a kilo of fat per week, you'd want to aim for a deficit of around 500 per day. So, if you normally eat 2500 calories per day, you would reduce this to 2000 per day. Generally speaking, this moderate deficit is considered a safe and sustainable approach to weight loss.

Below, you'll find some handy calculations for figuring out how many calories to eat, depending on your goals. However, as a general rule of thumb, you'll want to avoid dipping lower than 800 to 1000 calories per day. Eating fewer calories than this may seem like a good way to fast-track weight loss, but tends to be unsustainable (cue, yo-yo dieting) and cause metabolic damage over time.

Individual factors that affect calorie needs

There are several variables that can affect how many calories you should consume.

One factor is your goals. For example, if you want to lose body fat, being in a calorie deficit is key. However, if your goal is to change your body composition or get more 'toned', this is where things can get a bit more complicated, as you need to ensure you're eating enough to build or maintain muscle. Meanwhile, if weight loss maintenance is your goal, you'd eat the same amount of calories that you burn.

Another factor that affects how many calories you should eat is your level of activity. If you have a sedentary job that mostly involves sitting at a desk, you are going to require fewer calories than someone who spends most of the day on their feet.

Other key variables for calorie intake are your height, weight and gender. Men typically have a higher calorie requirement than women, due to being larger, having more muscle mass and other biological factors.

How to calculate your calorie intake

To determine how many calories you should be eating, you'll need to know your basal metabolic rate (BMR) — the number of calories your body burns at rest to perform essential functions. There are a couple of different formulas you can use to calculate this, but the most common is the Harris-Benedict equation [5].

For women, this looks like this:
BMR = 655.1 + (9.563 × weight in kg) + (1.850 × height in cm) - (4.676 × age)

If you know your body fat percentage (by using smart scales, for example), you can also use the Katch-McArdle formula, which considers lean body mass [6].

BMR = 370 + (21.6 × Lean Body Mass in kilos)

Using body weight and activity level

Once you have your BMR, you can use this to determine your TDEE (total daily energy expenditure). This is the total number of calories burned in a 24-hour period, including basic bodily functions (like breathing and digestion) and activity.

To calculate your TDEE, you multiply your BME by your PAL (physical activity level). The PAL levels include [7]:

• Sedentary (little to no exercise): 1.2
• Lightly active (light exercise or sports 1-3 days a week): 1.375
• Moderately active (moderate exercise or sports 3-5 days a week): 1.55
• Very active (hard exercise or sports 6-7 days a week): 1.725
• Super active (rigorous exercise and a physical job or training twice a day): 1.9

Online calculators

Hate maths? Thankfully, there are some reliable — and free — online calorie calculators you can use to take the guesswork out of the process. Simply enter your age, sex, height, weight, and activity level and let it do the work for you.

Seek professional guidance

There's no reason you have to figure it all out by yourself. Even professional athletes have a team of expert advisors to keep them on track.

A good nutritionist, dietitian, personal trainer or health coach will help you figure out your ideal energy intake while taking Mounjaro. They'll also give you a breakdown of your macronutrients (protein, carbohydrates and fat), to ensure you're fuelling your body adequately.

When you sign up for the Juniper Programme, you don't just get a prescription for Mounjaro. You also gain access to expert guidance on exactly what foods you should eat to achieve the calorie intake needed to achieve your goals.

The proof is in the pudding, as data shows that combining weight loss medications with nutrition coaching achieves better results than through medication alone [8].

Why diet is important when taking Mounjaro

You've likely heard that "a calorie is a calorie." That is, it doesn't matter if you eat nothing but junk food or solely salads — if you're in a calorie deficit, you're going to lose weight either way. While there is some truth to this, not all foods are created equal.

What to eat on Mounjaro

Many people find that they are no longer able to eat large portions while taking Mounjaro. In order to keep your energy levels up and avoid fatigue, it can be a good idea to aim for smaller, more frequent meals that are nutritionally dense. Here are some broad dietary guidelines to keep in mind.

Protein-rich foods

When it comes to long-lasting Mounjaro weight loss, protein will be your best friend. By getting in plenty of protein, you can maintain as much muscle mass as possible. This helps set you up to maintain your weight loss even if you stop taking Mounjaro, as it keeps your metabolism performing efficiently.

So, how much protein should you eat, exactly?

While it varies for everyone, a common recommendation is to consume 0.8 to 1 gram of protein per kilogram of total body weight per day [9]. Good sources of lean protein include lean meats like chicken, turkey, red meat, fish and animal products like eggs, milk and Greek yoghurt.  You can also go for plant-based protein sources like lentils, beans, tofu and nuts, or even protein shakes.

Fibre-filled fruits and vegetables

Some of the more common side effects of Mounjaro are gastrointestinal issues [10]. This might include bloating, gas, constipation and diarrhoea. While these symptoms are usually temporary as your body adjusts to your dose, loading up your plate with high fibre foods can help keep you 'regular.' Think leafy greens, berries (such as strawberries and raspberries) and starchy vegetables like sweet potatoes.

As added benefits, these foods tend to give you sustained energy and keep you full for longer, giving you more bang for your dietary fibre. They can even help speed up weight loss on the scales, by getting your digestion moving when you're 'blocked up.'

Healthy fats and whole grains

As many people find they have minimal appetite on Mounjaro, there's an increased risk of developing nutrient deficiencies. Making sure you're still getting enough nutrients and vitamins is key to maintaining your energy levels and overall health.

Following a 'balanced plate' model means also combining your protein with sources of good fat and complex carbohydrates. Think, overnight oats with nut butter or mixed vegetables with fatty fish and brown rice.

Balancing diet and weight loss injections

While medications like Mounjaro undoubtedly make it easier to consume fewer calories, they're not a magic bullet. It's still important to keep an eye on your calorie intake and overall nutrition to help make weight loss reliable.

By ensuring you're supplementing your weight loss injections with a balanced diet rich in nutrients, you can feel and look your best at every stage of the journey.

At Juniper, we support weight loss by not only telling you how many calories to eat, but also providing holistic guidance and delicious meal plans so you actually enjoy the process.

Ready to see if Juniper is right for you? You can check your eligibility here.

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