The truth about protein shakes, according to science

Protein-rich diets have been popular for some time. Everything from chocolate bars to ice cream is emblazoned with the promise of ‘high protein’. Influencers and media outlets seem to rave about the weight loss and muscle-building potential of eating a lot of protein.

But when it’s added as an extra ingredient, along with additives, emulsifiers, and sugar - is it really helping our muscles grow?

You’ll finish this clear on where the best place to get your protein is. 

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Transcript

[00:00:00] Jonathan Wolf: Hello and welcome to ZOE Shorts, the bite-sized podcast where we discuss one topic around science and nutrition. I'm Jonathan Wolf and today I'm joined by Dr. Federica Amati and today's subject is protein bars and shakes. 

[00:00:16] Dr Federica Amati: That's right Jonathan. We've had so many questions from our listeners on this one.

Protein-rich diets have been popular for some time and you see influences in media outlets raving about the weight loss and muscle-building potential of eating lots and lots of protein. 

A lot of people find that reaching these targets can be really hard with food, so they boost their intake with protein bars and shakes.

[00:00:38] Jonathan Wolf: So Federica, my question then is, do we really need all that protein? And are these bars and shakes actually healthy for us? 

[00:00:46] Dr Federica Amati: We're going to cut right through the marketing noise and find out whether this stuff is actually good for you. 

[00:00:51] Jonathan Wolf: Okay, let's shake up some myths and unbar the truth then.

So, Federica, I'd like to make a quick introduction for listeners who don't feel they really know you yet. You're a lecturer at Imperial College London and you're the author of the best-selling book Everybody Should Know This and we're fortunate enough to also have you as our head nutritionist here at ZOE and I know you spend a lot of time thinking about this topic.

It feels like the very word protein is so widely used these days that we should all completely understand what it is. But actually, each time it comes up, I realize I'm not really sure I do. 

Federica, what is protein? 

[00:01:30] Dr Federica Amati: Okay, Jonathan, so proteins are really cool. And it's just the word, though, that we use to describe the very complex 3D structures that are made up of different amino acids that all join up in really long chains.

So these long chains of amino acids then fold over themselves in super complicated ways and they form different proteins when they're this complex 3D structure. 

Protein is found everywhere in the body, bone, skin, hair, enzymes, and immune system cells. So, Jonathan, you contain more than 10,000 different proteins. It's a really big part of what you're actually made of. 

[00:02:08] Jonathan Wolf: And what is protein made up of? 

[00:02:10] Dr Federica Amati: So, protein is made up of 20 different amino acid building blocks. Think of it like amino acid letters in the protein alphabet that make up each human being or like little Lego bricks that make up structures. 

Nine of these amino acids are called essential amino acids and they must come from food. We cannot make them. But the rest of them we can actually make in the liver by disassembling existing proteins into their amino acid components and then modifying them into the amino acid that's needed. Which is pretty cool. 

[00:02:41] Jonathan Wolf: That is cool. And I feel like the liver is an underappreciated organ and deserves more love.

I feel like there's the heart that's pumping away and the lungs that are going in and out and they're very glamorous. And I feel the more I learn from you scientists, it feels like my liver is doing a great deal. Sort of like the backing singers that don't get the full credit for their addition to the music.

[00:03:04] Dr Federica Amati: The liver is the absolute master metabolic organ. It literally is a center central hub of our metabolism. Without it, we would not be alive. Right? 

We all know that when a liver fails, liver failure leads to death. The liver is so essential. It definitely needs much better PR. 

[00:03:24] Jonathan Wolf: Bringing us back to protein, do we need to consume protein in our diet? 

[00:03:27] Dr Federica Amati: Yes. So absolutely we do need protein from our food. It's essential to support hundreds of processes at a cellular level and to really give us our structures. 

So, it ensures that we can maintain an adequate amount of lean muscle mass, it strengthens our bones, it helps to ensure that our immune system can function properly.

Crucially, we have evolved to absorb protein really well. We find all 20 amino acids in all plant foods, and many people regularly eat lots of healthy protein-rich foods, including eggs, whole grains, nuts, beans, seafood, and white meat. 

[00:04:00] Jonathan Wolf: So I think that brings us on to the key question, which we have talked about on a couple of podcasts in the past.

How much protein do we need to be eating? 

[00:04:09] Dr Federica Amati: Exactly. So, there are guidelines for how much protein we should consume. 

The daily recommended amount and this is agreed by the WHO, and lots of intelligent governing bodies, by lots of big agencies, is 0.83 grams of protein per kilogram of body weight for adults.

[00:04:27] Jonathan Wolf: Okay, so I weigh a little over 60 kilograms, which means I should be eating roughly 50 grams of protein every day? 

[00:04:34] Dr Federica Amati: Right, and in the U.S. on average, adults are eating an average of a hundred grams in a day. So this is almost twice the amount that they need. 

Now in the U.K., one analysis actually found that people's protein intake was 75% higher than the recommended amount.

[00:04:50] Jonathan Wolf: So the chances are, if you're a listener right now, you're very likely, it sounds like, to actually be getting more than enough protein. 

[00:04:57] Dr Federica Amati: That's exactly right, yeah. So most people don't need extra protein, so long as they're eating enough food throughout the day. That's really critical. So there are, as always, some exceptions.

Children actually need more protein than adults in terms of grams per kilogram, as do pregnant women, because they're building new tissues all the time. Now, both of these groups can still get all the protein they need from whole foods. 

Later in life, we may also need a little bit more protein because we just become a bit less efficient at absorbing protein from food. This is typically as we age over the age of 70. 

You may also need protein if you're training very, very hard in the gym, Jonathan, at elite athlete level. But if you're not, and I think the majority of people aren't, it's extremely uncommon for healthy adults in high-income countries to have a protein deficiency.

It just doesn't happen. And there are researchers questioning if the daily recommended allowance actually needs to be revised or even lowered. 

[00:05:59] Jonathan Wolf: And I think it's safe to say, Federica, as you said that, that you do not feel that I'm training very, very hard at the elite athlete level. 

[00:06:05] Dr Federica Amati: No, I mean we're really talking about athletes who are training eight hours a day and their overall food requirement, energy, protein, micronutrient is so high that they need to eat so much more food in general than we would.

And that added protein they need, they'll be getting that from the massive amounts of foods that they need to eat. 

[00:06:25] Jonathan Wolf: So I'm definitely not in this category. 

So if we're getting enough protein from our normal diet, so if the vast majority of people you're describing are doing that, where is it coming from and can you give some examples? 

[00:06:37] Dr Federica Amati: Sure. So one of my favorite breakfasts is a bowl of yogurt with some kefir, nuts, seeds, and berries that has more than 30 grams of protein in it. Then if you're having maybe two eggs, some butter beans, tomatoes, and spring onions, That's already 30 grams of protein as well. A small salmon fillet contains around 30 grams of protein too.

So it's easy to see how individual meals can easily get to 30 grams. 

[00:07:00] Jonathan Wolf: And so in all those examples, that's a small part of your total amount that you eat in the day and you've already got to 30 grams, which is more than half the amount that we were describing that I would need to eat.

[00:07:12] Dr Federica Amati: That's right. Exactly. 

[00:07:13] Jonathan Wolf: Now, what about if I'm eating plant-based meals, so I'm not eating any meat, for example? 

My son, who's a 16-year-old teenager growing fast, is convinced that if he doesn't eat meat, he will not get enough protein and he will not manage to be six foot tall, which is where he's headed, or at least his ambition.

[00:07:35] Dr Federica Amati: So, there's plenty of protein in plants. We talked about earlier that all plants contain all 20 amino acids, so the building blocks are all there. Some plants contain more protein than others and plant protein just needs a bit more work to absorb than animal protein. 

But let's take a cup of cooked lentils, right? It's not a lot of lentils. That has around 18 grams of protein in it. So you can imagine that by eating plenty of plants, you will be getting more than enough protein that you need. 

And there's really strong evidence to support that the beneficial effects of a high plant protein diet is much better health-wise than a diet high in animal protein.

[00:08:12] Jonathan Wolf: Got it. And I think one of the things I hadn't fully appreciated because I didn't know anything about nutrition seven years ago is there's a lot of protein in things like yogurt and cheese and eggs and things like this as well. 

So it's not just protein equals a large piece of red meat. 

[00:08:31] Dr Federica Amati: Yes, and it's not just a dry chicken breast or the same salmon fillet every single day. Exactly. We can definitely change it up with lots of delicious and nutritious foods. 

[00:08:42] Jonathan Wolf: So you're describing so many different forms of protein in our diet, and yet I am constantly seeing advertising suggesting I'm not getting enough. And when I go into the grocery store now, almost every other food has this big label saying, contains protein or added protein.

Why am I getting all this stuff suggesting I'm not getting enough? 

[00:09:06] Dr Federica Amati: Yes, I mean, I think it's really interesting, isn't it? Because we've seen protein supplements have exploded in popularity. And they're a huge market. And we've seen things like breakfast cereals that add protein, sliced bread without a protein, chocolate bars and ice cream.

These are foods that you don't need. They're not supposed to be a source of protein in our diet. They're not designed to be a really good source of protein. 

[00:09:29] Jonathan Wolf: Ice cream with added protein. 

[00:09:31] Dr Federica Amati: Yeah, so you can get high-protein ice cream. Now, Jonathan, you can imagine that the additives in that ice cream are quite wild.

This constant marketing of, you need more protein, you need more protein, means that people are actually willing to spend, on average, about 20% more money on foods that have a protein sticker on them. Which is wild. 

[00:09:50] Jonathan Wolf: That is wild. I'm picturing walking down my local grocery store aisle now, and I can see not just sort of the protein shakes and the supplements, but also the granola bars and the cereals that sort of have this word protein plastered on their packaging now.

[00:10:06] Dr Federica Amati: It's a big business. The global protein supplement market size was valued at 5.83 billion with a B in 2022, dollars. Now, we're constantly told that we need to eat more protein, so the marketing is creating the demand. 

[00:10:21] Jonathan Wolf: So let's talk about this protein that's added to these foods instead of just sort of being in them already. Where does that protein come from? What's it made from? 

[00:10:29] Dr Federica Amati: Yeah, so these supplements are made by extracting protein from animal or plant-based materials. That might be eggs, peas, hemp, rice, soy, or cow's milk. And the extraction process often requires a lot of industrial steps, so you wouldn't be able to do this at home.

But the thing is, protein bars and shakes don't contain only protein, right? They've often got a bunch of other things in them like added sodium, sugars, thickeners, emulsifiers, and other additives to make them look, taste, and smell more palatable than pure protein would. 

[00:11:03] Jonathan Wolf: Now we've talked about ultra-processed foods in other podcasts and the way the evidence is showing more and more clearly that they can be harmful for us.

What you're describing there just sounds like a description of an ultra-processed food. 

[00:11:17] Dr Federica Amati: Exactly, Jonathan yes. These protein drinks, and the bars especially, are very often completely ultra-processed foods. They're food-like products that contain lots of ingredients you would never have in your kitchen, and that you would, frankly, never make at home.

Take, for example, a chocolate protein bar. It has protein added as a separate ingredient, but it also is likely to be high in sugars and oils, gelling agents, and a long list of emulsifiers, sweeteners, and thickeners that you would normally never add to your food. 

I mean, sometimes if you look at the back of a pack of one of these bars, it's wild how long the ingredients list can be. And what's more, a lot of the added protein foods hardly have that much protein at all. 

So you might be spending this additional 20% of your money to buy high-protein ice cream, which actually only has 10 grams of protein. But you have to eat a third of the tub to get that. So you can get 18 grams of protein from one cup of edamame beans, and it'll be a lot more nutritious than the ice cream.

And this obsession with adding more protein to our diet has moved us away from adding more real foods to our diet and towards adding foods that we really don't need to be eating. 

[00:12:22] Jonathan Wolf: Wow. So standing in the grocery aisle, I think you're saying I need to ask myself, firstly, do I actually need this additional protein?

And then secondly, is it worth getting that additional protein for the trade-off of consuming all these other ultra-processed ingredients? 

[00:12:40] Dr Federica Amati: Exactly. And I mean, I would argue that the trade-off is larger than you might expect. We're seeing increasing evidence that links ultra-processed foods to heart disease and early death.

So whatever you're buying this protein for, it's probably not those things, is it? 

[00:12:53] Jonathan Wolf: No, I think no one likes to be buying early death, Federica. So I think it's a safe bet that that is not what they're thinking when they're buying the label, the extra protein. They actually think they're buying extra health, right?

So I think it's another example of the sort of shocking mismatch between what you're allowed to put on the labels of foods, whether that's in the U.S., U.K., really anywhere in developed countries, and what the latest science is actually saying about it. 

So why isn't this more regulated in terms of how these foods are manufactured? The team did some research and suggested that actually these protein supplements aren't really even very regulated. 

[00:13:31] Dr Federica Amati: Jonathan, supplements generally aren't regulated, right? So you can make a supplement and claim it to be a high protein supplement or good for muscle growth or whatever, but there's actually no regulation in place to stop you from making that claim if it's not true.

You can look out for specific accreditations from the sports industry that try to accredit proteins for athletes. So there are things you can really look out for. But generally speaking, they're considered a dietary supplement, not a food or a medicine. 

So manufacturers are the ones that are responsible for testing their own products and ensuring that they're safe and made with good quality ingredients. So we're relying on the manufacturers to be honest about it, essentially. 

[00:14:10] Jonathan Wolf: And let me guess. Some of them don't. 

[00:14:13] Dr Federica Amati: That's right. So, in 2017, the FDA in the U.S. inspected 656 dietary supplement production facilities and found violations in more than half of them. The most common was actually the failure to establish purity, strength, or composition of the final product, which is a pretty key trifecta there, and yet the global market continues to grow.

Here in the U.K., the sports nutrition market grew 160% since 2011. So it seems like more and more people are buying these supplements. 

[00:14:44] Jonathan Wolf: So Federica, we've talked about what role protein plays in the body, why we need protein, and how some of these supplements are produced. So how do they actually affect our body?

[00:14:54] Dr Federica Amati: So first of all, let's look at the gut, right? If you eat a lot of protein, more undigested protein reaches your gut bacteria, so there's more amino acid metabolism in the gut. 

[00:15:05] Jonathan Wolf: And is that good or bad? 

[00:15:07] Dr Federica Amati: So right now it's unclear, but what we do know is that impaired gut health could lead to nausea, dehydration, constipation, and other gastric issues. And more research is needed to understand the specific ramifications of protein on the gut microbiome. 

[00:15:23] Jonathan Wolf: And can we talk about weight loss? Because that seems to be why a lot of people are drawn to the idea of high-protein diets. 

There's been a whole bunch of media talking about this promise that you're going to get a leaner body if you eat this extra protein. And I think that's part of the reason that the ice cream tub has added protein stamped on it. 

[00:15:42] Dr Federica Amati: There is good evidence to show that when you eat protein, it really helps to contribute to the satiety signals that help you to feel full. So it might aid weight loss, especially because it helps with this feeling of fullness.

And also, with protein, we require more energy to break it down compared with like, for example, carbohydrates. But there's also really good evidence that we all respond to protein differently. And I really want to draw this back to the quality of protein being so important, and why we should be including more plant protein.

So, eating protein causes insulin to be secreted, right? Going back to the liver, it's a really important role, it tells the pancreas to release insulin. So you can imagine that if you drastically increase protein intake or have consistently high protein intake throughout the day with lots of protein snacks and bars and shakes, you actually increase your risk of becoming insulin resistant, which impacts our metabolic health.

It's like a key part of our metabolic health is our insulin sensitivity. We have evolved to absorb these nutrients from food which takes longer to break down and to get absorbed into the liver compared with these ultra-processed foods that contain protein, or these shakes. 

[00:16:53] Jonathan Wolf: So what about protein for muscle building? So I think that's the other big area where I hear that a lot and I've already described my son.  

That's definitely the association that I have with protein powders. So, people lifting really heavy weights in the gym and then throwing back the protein shake afterwards.

I remember when I first started in the gym, which was almost a decade ago, I remember being told that I needed to eat more protein as part of this, and I started drinking these disgusting chocolate whey protein shakes in order to build more muscle. Does it work? 

[00:17:30] Dr Federica Amati: So, there's good evidence to show that when you consume protein and you're doing heavy weight lifting, the two things together can help with muscle tissue growth, right? So, I have to really stress here that you have to be lifting quite heavy weights, doing strenuous physical activity that is really pushing the boundaries of what you can already do.

But it appears that consuming 20 to 40 grams of protein at a time, so like we described in the meals that we talked about earlier, is enough, and you can eat that throughout the day. There isn't this magical window that you have to knock back a protein shake in immediately after a workout to maximize its benefits.

You could actually just eat a lovely meal, get a fillet of salmon, or have some eggs for breakfast, add some beans, maybe have some lentils or some mixed nuts on the go. If you're on the go and you're feeling hungry, again, consider grabbing something like kefir, which is high in protein, or a handful of mixed nuts, or some hummus with chopped vegetables.

Basically, Jonathan, what I'm trying to say is that if we're consuming excessive quantities of protein, it doesn't have any health benefits or body composition benefits by itself. 

The other crucial point is that you have to be doing some kind of weight or resistance training in order to see a body composition change together with a healthy, varied diet. Proteins coming from whole foods, consuming extra proteins in bars or in shakes alone will not result, to be honest, in any benefit.

[00:18:56] Jonathan Wolf: So pulling this together, I love this idea that you're saying you don't need to consume the protein within a few minutes of doing your exercise. Because that was definitely sort of what I was taught when I first went to the gym. 

And in retrospect having done a lot more of these podcasts and talked to a lot of these scientists, I'm like, it sounds sort of crazy. If I imagine back to our ancestors in East Africa somewhere, they've been pounding across the savanna, chasing after this animal for hours and hours, they've done all of that, their muscle damage, getting there, they then drag the thing all the way back to their camp, cook it all.

It's obviously hours and hours and hours and hours later, they finally eat any of this and you're like Oh yeah, well it's too late, we're not gonna be able to repair any of the muscle damage you needed to eat that raw. 

It's obviously ridiculous. And so as soon as you say that, it sort of becomes obvious that your body is going to be fine.

But what I think I understand is we listen to this stuff that like the ultra-elite athlete that you were describing earlier does where they're trying to get the 0.01 second improvement and they're figuring out how to optimize their diet in some crazy way. And then we start to apply it to ourselves where maybe you go to the gym a couple of times a week and it’s not really an analogy anymore, is it, Federica? 

[00:20:15] Dr Federica Amati: Exactly, Jonathan. I think that's what's really funny about it, is like, of course, there's exercise nutrition for elite athletes. It's like a different science. There's lots of considerations, not just on protein, but on electrolyte loss. Because these people are pushing the limits of human physical capacity, right?

The 99% of us are not in that category. And I think what's happened is that often people think if they go to the gym three or four times a week, and then they maybe go for a run as well, they might need to start thinking in that way, but that's not the case. 

What you just said is exactly right. We have evolved over millions of years. Evolution is really smart, right? Our bodies are very efficient and they're built to make us stronger and to make sure that we live a long and healthy life. All we need to do is provide the right fuel. And I feel pretty strongly that the right fuel does not include protein shakes and protein bars, right?

It's as simple as that really, that's what it comes down to. If you're eating enough whole foods in your diet, plant and animal, whatever your preference, concentrating on that variety and on making sure that you're getting as much whole food as possible with lots of fiber is going to help you get to whatever your health goal is.

I will put one small caveat here, Jonathan, there's always a caveat there. And for some people who have impaired absorption issues or who have to feed through a gastric tube, for example, ultra-processed shakes that contain added protein, they're obviously life-saving. So there's always a medical condition that might require these products.

But here we're talking about most of our listeners who are listening to this podcast that will resonate with the fact that maybe they've been hyper-fixating on getting enough protein every single day. And they're probably making food choices for these snacks, for these bars and these shakes that are actually detrimental to their health.

So I want to just help people to reconnect the power of food to get us where we want to get to without the need for these products. 

[00:22:09] Jonathan Wolf: Alright, so the conclusion is no to the protein bars and shakes, and no for most people to this terror that they're not getting enough protein. 

[00:22:18] Dr Federica Amati: Exactly. And yes to eating more foods that will help you feel great across all of the metrics and to reach all of the goals, not just looking like Arnie Schwarzenegger when he was competing. 

[00:22:29] Jonathan Wolf: Now, if you've listened to this and you'd like to take the first steps towards more energy, less hunger, and more healthy years, then take our quiz to unlock new food choices that you could be making right now.

Simply go to zoe.com/podcast, where as a podcast listener, you can also get 10% off. I'm Jonathan Wolf. 

[00:22:47] Dr Federica Amati: And I'm Federica Amati. 

[00:22:49] Jonathan Wolf: Join us next week for another ZOE podcast.