Let's tackle a meaty topic.
Everyone seems to be going on about protein. Everyone in the gym is chugging shakes. People on the internet are claiming its the secret to weight loss and everything else. Other people on the internet are saying the first people's kidneys are going to fail. Someone else says there's really no need to worry as we don't actually need much protein after all. Some people have numbers, but those numbers are all different. Everyone is confused.
Who is correct?
Well, everyone is a little. Save that they are all only telling a very small part of a bigger story. So shall we break it down? WITH SCIENCE!
OK, so a figure you will often see bounced around is 0.8g of protein per 1kg of bodyweight. This is the Recommended Daily Allowance. This figure is based on the idea of a "normal" person who is not particularly active, or growing and consuming an adequate amount of calories per day. This figure is the amount of protein they should eat to avoid malnutrition. This is key. It's not an ideal or optimal amount, it's a minimum.
Let me give you an example. Janet is an office worker who does Zumba once a week. She is not on a calorie controlled diet. She weighs 70kg. Using the RDA as a reference, Janet needs 56g of protein a day.
If Janet eats 2 palm sized portions of lean, high protein foods a day - say a can of tuna for lunch and a a chicken fillet for dinner - along with a reasonable balance of other foods, she will exceed that amount of protein no problem. In fact a large (200g raw) chicken breast has about 40g, so really, one large portion with dinner will do it (considering that there will be protein in other foods she eats, like veg and bread).
It's pretty easy to hit that amount, so long as you are consuming one large and one small-medium meal a day that looks like the Eatwell Plate. So for Janet there is no need to worry and no need to supplement.
Protein deficiency is not a big problem in wealthy, developed countries. So the people who say we have nothing to worry about are correct...but....
There is good evidence that a higher protein intake would benefit "average" people in terms of health, metabolic function and increased satiety (feeling full after meals - that means less urge to have unhealthy snacks).
Protein for fat loss.
Or are they? Let's say Janet decides she would like to shed some pounds. So she goes on a restricted calorie diet. She's in deficit, consuming less calories than she expends.
When your body finds itself short of fuel, it looks for an easy substitute. We hope that it chooses fat, but it will also merrily go for muscle (everyone scream "NOOOOOOOOOOO"). However, you can change this, with food.
Food isn't just calories and macros, food is also communication. What you put into your face tells your body how to function, how to balance your metabolism, even what genes to express.
Studies show that if you eat double your RDA of protein (that's 1.6g per kg bodyweight) while on a calorie deficit you will lose more fat and less muscle mass (Alan Aragon Research Review, June 2013).
So, back to Janet. If she eats 112g of protein a day, as well as making sure she is expending more calories than she eats (no weird tricks remember) she will lose fat mass effectively and retain more of her muscle mass. Also, because protein is slow to digest and likes to hang around in the stomach for longer, she will feel more satiated by her meals and find it easier to eat less.
Eating 112g of protein a day is going to take a little bit of effort. That's a solid portion of protein 3 meals a day. If Janet is a cornflakes for breakfast kind of person, she's going to have to think about maybe converting to eggs on granary toast (that's about 25g protein) or suchlike. Eating a larger amount of calories as protein, means shifting about the proportions of other foods too. You can't just eat a load of extra calories as protein! Fat is important, so it's carbs that will be cut back. That might mean swapping a ham salad baguette for a chicken and edamame bean salad. For dinner she might have to consider forsaking low protein density foods like fishcakes for a higher protein density food like fish fillets. She might find making these changes difficult to achieve consistently, and consider taking one protein shake a day to "top up", but the rule with supplements stands "real food first".
You don't need to count or track your protein grams if you are on a plan like Janet. You just need to think about building your meals around your proteins. Start by deciding how you are going to get the protein onto your plate and build around that, adding healthy fats next, and carbs last.
Protein for athletes
Athletes (and in this I am including people who train a lot, for whatever purpose) are aiming to build muscle, whether they are runners trying to get their legs stronger, baseball players wanting to hit harder or strength athletes wanting to lift more. Even a casual sports player is causing minor damage to their muscles every time they play. Protein is vital for the growth and repair of muscle tissue, so anyone who exercises with moderate to high intensity on a regular basis is going to need more than the RDA of protein.
Recommendations for protein intake for athletes vary between different institutions based on different studies. This makes sense because the actual work done by "athletes" can vary wildly. That said, the range is fairly consistent at 1.2 to 2g of protein per kilogram of bodyweight.
So lets have a new example. Amy is a figure competitor (that's bodybuilding). She's in a bulking phase, which means she is trying to pack on as much muscle as she possibly can. She lifts weights in high volume on a daily basis. She weighs 60 kg.
In order to recover well from her training sessions and build large amounts of juicy muscle, Amy is going to need to go for the upper end of the recommendation, about 2g of protein per kg bodyweight. That's 120g a day.
Hitting that target is going to mean, just like Janet on her weight loss plan, that Amy is going to have to eat 3-4 good portions of protein a day - either as dense protein sources like meat, or by consuming multiple plant based proteins.
Amy's diet is going to take some planning, but it's still going to be comfortable, good food. It's perfectly possible to consume this amount of protein without needing supplementation.
Protein for cutting
OK, so now we are getting serious. Amy is preparing for competition. She wants to reduce her body fat to show off those muscles she's been working for, but she also really doesn't want to lose too much of that muscle.
Lean, trained athletes in a calorie deficit need to take on a higher amount of protein in order to maintain their existing muscle, continue to recover from their training and persuade their metabolism to burn through that stored fat.
Recommendations for this level tend to come from coaches with experience - they know what works - and Amy is probably looking down the barrel of 2.6-3.1g of protein per kg bodyweight. Every. Single. Day.
So here is the balancing act, for simplicity, let's say she's aiming for 3g/kg. That's 180g of protein a day. Or to put it another way, about 6-8 portions. That's a lot.
It's even more when you consider that with a fat loss goal, she's going to be eating a deficit of calories. Let's for giggles assume she is eating all that protein as chicken breast - she'd need to eat about 900g of chicken breast which is 1100 kcals. That's not going to leave her with much for chips.
And this, dear reader, is why bodybuilders need to eat so differently from your average person.
If Amy gets all her protein from real food, she probably only has about 800 calories to "spend" on other foods that give her the vital nutrients she needs to live - like the fats she needs to - bizarrely enough - persuade her body to burn fat as a fuel. And the fats and carbs she needs to fuel her intense lifting regime. Not to mention the vitamins, minerals, phytonutrients etc she needs from a fresh, whole food based diet.
If Amy drinks a protein shake, she can get the same amount of protein as she would have from the chicken, with about 20% less calories, and when you are cutting it that fine, that makes a difference. If she takes a BCAA supplement (high amounts of specific proteins, very low calorie) she can give herself even more wiggle room.
This kind of diet is difficult, uncomfortable and not great for her health, but it is also only a short term measure to prepare for a competition - she will adjust her diet, and put some fat mass back on, once she has that trophy.
Protein and kidney damage
I get asked about this a lot. People are very worried about this. Whenever I see a friend posting on social media about increasing their protein intake, or having a protein shake, there is always someone who is worried about their kidneys. So what's that all about?
A healthy person's kidneys can healthfully process 3.5-4.5g per kg bodyweight of protein per day. Let's call it 4 and for Amy that would be about 240g.
Is Amy going to exceed that by eating a healthy diet? No. Not even on a high protein diet (say 40% of calories as protein) she's not going to surpass that into dangerous territory. That's a LOT of chicken breast. And let's remember, 240g is not a dangerous amount, it's an amount that her kidneys should be able to handle, day in day out. To see actual kidney damage she would need to consume more than that, consistently.
Is it possible to exceed that by being ridiculously irresponsible and mindlessly quaffing protein shakes? Absolutely. Making 2 scoop shakes Amy could hit 240g on 6 shakes a day before she had eaten anything else. And this is why you don't take nutrition advice from the gymbro who is always curling with one hand and mixing a shake with the other.
Is it possible to accidentally eat too much protein while eating to hunger? Probably not. If you ate just chicken breast, that would be around 1.2kg (from raw) each and every day. That is an obscene amount of chicken, I don't believe a 60kg woman would feel hungry after half of that, she certainly wouldn't have the appetite. With other foods balancing it out, she definitely wouldn't be hungry enough.
So there it is. Eat whole food first. Supplement only if you can't hit a particular portion (like that day when you only have time for toast and a shake at breakfast). Eat a balance of proteins, fats, veggies and carbs. Following the Precision Nutrition portion guide is a great start.
Some people with reduced kidney function do need to be on a lower protein diet. Those people should be getting their dietary advice from their doctor or registered dietitian. Not their personal trainer, nutrition coach, gymbro pals or people on the internet.
If you are struggling with managing your diet, whether for weight loss, muscle gains or athletic performance, why not get in touch with me about nutrition coaching. I work with individuals and groups to help them build healthy habits that make fuelling their lifestyle easy, natural and comfortable.
I also offer both in-person and online personal training; and customised exercise programmes.