Protein Shake Instead Of One Meal A Day? (The truth)

Sometimes clients ask me if they can be replacing one meal a day with a protein shake?

Replacing one meal a day with a protein shake can be beneficial if you’re looking to reduce excess weight. Having one less meal and replace it with a protein shake will help you reduce calories and ensure you have enough proteins in your diet.

should i be replacing one meal a day with protein shake

However, there are other ways to reduce excess weight and they doesn’t involve relying on protein shakes.

How Much Weight Can I Lose With Meal Replacement Shakes?

You can lose 1-2 lbs per week with meal replacement shakes because they will create a caloric deficit. People do more intense restrictions in favor of fat loss. However, in the long term, it can bring you more harm than good because lowering the calories further can lead to unwanted overeating.

In other words, more restriction doesn’t guarantee better results. Caloric deficit leads to putting extra stress on the body and if this stress will add up and continue over a long time it can trigger binge eating (source).

meal replacement shakes

Then we feel guilty and shameful, so we end up adding even more restriction and more stress.

The easy way out is to focus on a small and achievable changes that can be done over time. This build up the habits and help you reduce the stress, not add more.

You may see multiple articles of people claiming that you can replace your one meal a day with some super shake. And usually, in the end, they want to sell you that shake.

And that’s just the sad reality. They don’t care if will you get results or not. They don’t care is that healthy for you or not. All they care about is the sale.

Today is so easy to get endorsed by influencers (that are paid to do so) to promote any diet product claiming it works. And because people are naive and uncertain and they want to look like those influencers, they believe them.

I’m not saying that meal replacements are bad. In fact, research is clear that meal replacements are proven to be a valid option for the management of overweight and obesity (source).

They work.

But so does any other diet that is on the market. Any diet that puts you into a caloric deficit will work. But people quit. Why? Because they cannot do it in the long term. It’s not about what works best fast. It’s about what works and what you can sustain for the long haul.

And the problem is when you stop doing those shakes, your weight is gonna go back up again. Just like any diet that you are on and then fall off the wagon.

Can I Just Have Meal Replacement Shakes?

It is not recommended to have just meal replacement shakes during the day because the results are only temporary. Within the first week, people lose water weight only, not body fat. The moment you eat fewer carbohydrates, your body starts to eliminate excess water. Also, high protein diets lead to additional fluid loss.

Carbohydrates intake increases water storage in the body. For every gram of carbs, you store around 3-4 grams of water. So you may get excited that you lost a lot of weight but in the reality is just the water loss (source).

can I just have meal replacement shakes

Also when the body breaks down proteins and amino acids, it produces a by-product, urea. So the next step is to use more water to flush it out from the system. That’s why people feel like they are losing weight (source).

This water level manipulation tactic is well-known by world-class bodybuilders and physique competitors. Few days before the competition they reduce carbohydrates and increase sodium intake.

This will increase the water loss from the extracellular space, and as a result, will enhance the appearance of muscle. So when you step on the scale, you may notice the number goes down.

But this is not the fat loss. It’s a water loss. For the fat loss, you need time, more than a week or two. That’s why having the actual meal instead of shakes will help you get real results because it’s a long-term project.

Are Meal Replacement Shakes Bad For You?

Meal replacement shakes aren’t bad for you in the short term because they can reduce excess weight. However, in the long term it is not recommended to rely on meal replacements because once you stop drinking them, the weight will immediately come back up.

Besides, they don’t offer anything more than food. This means you can have the same or even better results on eating regular meals comparing to replacement shakes (source).

The whole idea of eating less is to get familiar with occasional hunger, and still get the nutrients that you need. Eating regular food not only delivers those nutrients but also helps you to stay energized throughout the day.

meal replacement shakes vs regular food

If you’re losing weight, but you feel like crap, it’s not worth it. Especially if your day depends on your energy. If you’re busy working all day and have multiple projects going on at once, meal replacement shakes will have a brutal impact on your performance.

There are several ways to reduce excess weight without meal replacements.

Can I Have One Protein Shake And One Meal A Day?

Doing one protein shake and one meal a day is an effective way to improve body composition and get enough proteins into the diet. People who are doing one meal a day can fail to eat enough proteins. Therefore having an extra protein shake will help to fill out this gap.

Doing OMAD with an extra protein shake is a simple form of intermittent fasting. Instead of eating only one meal a day, you add protein.

protein shake and one meal a day

Any successful diet has a commonality that is usually high on proteins. Regardless of being plant-based, keto, paleo, or carnivore, the more protein you have in your diet, the better your results (source).

So having an extra protein shake while doing OMAD is a great way to stay on the safe side.

One meal a day is a great way to reduce food intake. It works simply by restricting calories. You put your body into a caloric deficit. This means you switch from using an external source of energy (food) to using an internal source of energy (body fat).

It usually starts around 8-12 hours after your last meal. Your body uses the majority of the stored glucose and starts slowly to break down fatty acids for energy. And the longer you stay without food, the more fat your body will utilize.

But it doesn’t mean that longer fasting is better.

It’s more of a dose-response effect. For instance, if you have some skin infection, you may go to see your doctor. He will look at the symptoms and probably will describe some type of antibiotic for 7 days.

You take the recommended dose and seven days later the infection is gone.

But does it means if you double or triple the dose, will this infection go away quicker? No. In fact, you can get some serious side effects from taking too many antibiotics.

The same with fasting. It works in a small dose that you do consistently in the long term.

That’s why people break down on many meal replacement diets. They start with full enthusiasm.

Can I Drink Two Protein Shakes A Day And One Meal?

You can drink two protein shakes and have one meal a day because it will ensure that you’re getting enough proteins in your diet. Physically active people and people who want to reduce body weight need enough proteins daily, therefore adding two protein shakes will help to keep the daily requirements.

2 protein shake and one meal a day

This way you don’t add any additional calories, so you can stay in a caloric deficit, and ensure you will have enough proteins to stimulate muscle protein synthesis.

When you dieting it is imperative you keep up the good amount of protein. There is a whole laundry list of benefits and functions of proteins but for the weight reduction purpose those are the most important:

  • Proteins keep your satiety high
  • Proteins increase the thermogenic effect of food
  • Proteins preserve your lean mass

Which will all comes down to burning more calories and being full with less food. So one meal and two protein shake a day can get you there quicker.


I’m not saying that meal replacement shakes or protein shakes are bad or worthless. There is a time and place for it. They are very popular in all sports, athletic communities, and pretty much anyone who wants to gain muscle mass and stay lean.

They enhance muscle protein synthesis to build more muscle mass without adding additional food volume.

But if you’re looking for weight loss with OMAD, having one meal a day is already enough. And that’s all that you really need.

Michal Sieroslawski

Michal is a personal trainer and writer at Millennial Hawk. He holds a MSc in Sports and Exercise Science from the University of Central Lancashire. He is an exercise physiologist who enjoys learning about the latest trends in exercise and sports nutrition. Besides his passion for health and fitness, he loves cycling, exploring new hiking trails, and coaching youth soccer teams on weekends.

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