Simon Hill is an advocate of a plant-based diet. But as he told GQ, the definition of plant-based might be more flexible than you think. Hill’s entry into the plant-based world started when he was a teenager and his father experienced a severe heart attack at just 41. His father’s cardiologist told Hill and his brother that they’d need to exercise caution, as cardiovascular disease risk runs in families.
Now, he's got a popular health and longevity podcast, The Proof, and his 2021 book The Proof is in the Plants: How Science Shows a Plant-Based Diet Could Save Your Life (and the Planet) was a New York Times bestseller. (Perhaps more importantly, it received a positive 84% overall score from hard-asses at Red Pen Reviews.)
The 38-year-old Australian also spends time fact-checking fitness influencers with proof to support his claims. Unlike some other influencers that might populate your feed, Hill is a licensed physiotherapist with a master’s degree in nutrition. And he doesn’t seem to spend much time yelling shirtless in grocery stores.
Today, Hill’s podcast is a source of health information on range of topics that go far beyond beans and greens. Recent notable guests include Christopher Gardner, PhD, the researcher who led the vegan vs. omnivore twin study featured in the Netflix documentary “You Are What You Eat,” and bestselling author and OB/GYN Dr. Jen Gunter, who went on The Proof to debunk myths around the menstrual cycle.
If the myth that you can’t be jacked and plant-based is still around, Hill is personal evidence that that’s not the case. And so are some of his clients. As a nutritionist, he’s worked with stars including fellow Australian Chris Hemsworth, and is on the team at Centr, Hemsworth’s fitness company.
GQ caught up with Hill to talk about his favorite plant-based cuisines, developing his own health and longevity challenge, and whether we're all eating too much protein.
The most important thing for me is the quality of my food. Things like timing? I think they are important to a degree, but they're less of a priority for me. Particularly when I'm traveling, the number-one thing I focus on is just maintaining the quality of my diet. I'm trying to eat as much whole, minimally processed foods as I can. I have a bias towards getting protein from plants. I'm always seeking about: What foods on my plate are providing protein? I'm regularly eating things like tofu and tempeh, lentils, beans, chickpeas. Plant-based milks, like Ripple, for example—I have no affiliation with them—are quite high in protein. And around workouts, I'll have a protein powder.
I use a plant-based protein powder from a company called Momentous. They have an a really nice formulation that doesn't contain too many ingredients, has a great essential amino acid profile, which is important for recovery and building muscle after your training. And it tastes great. So that's what I use.
I'll also get some protein from nuts and seeds and whole grains, especially quinoa. But these are a lot less protein-dense than those other protein sources that I mentioned. So I have some focus on protein, and that's because I'm training a lot and I want to support that training. And then, in addition to that, I'm thinking about what are the other plants that I'm consuming throughout the day, I think diversity is really important. There is quite a bit of literature showing that diversity of plants is really critical to nourishing the microbiome. And when you do that, those microbes reward you by producing chemicals. In a way, the microbiome is kind of like our own personal pharmacy, and we can either nourish it or neglect it. I'm looking at making my plate colorful, and throughout the day trying to change exposure—different plants at lunch and dinner than I had for breakfast, and even thinking about the days previously, so that over a week, I'm exposing my microbiome to lots of different fruits and vegetables. I think that's sometimes overlooked. There's a lot of focus on macronutrients like protein and carbs and fat. But there are so many compounds in our food that don't provide calories that are really important.
I do have a particular focus on some fruits and vegetables, I think cruciferous vegetables like broccolini, broccoli, and cauliflower are really powerful, there's quite a bit of literature showing that they're associated with reduced risk of cancers. Dark leafy greens and berries are another two food groups I'm trying to make sure that I'm consuming on a daily basis—those are particularly good for brain health. There's evidence that some of the compounds in those food groups will help you with your focus, clarity, and memory on a day-to-day basis, but also protect you from neurodegenerative diseases like dementia in the long term.
Plant-based for me is an overarching term that encompasses multiple different types of diets. And they can be plant-rich, plant-predominant, all the way to plant-exclusive or what someone might describe as a vegan diet. So a Mediterranean diet, or a DASH [Dietary Approaches to Stop Hypertension] diet, that some people might be familiar with, those are technically plant-based dietary patterns, as is a pescatarian diet, as is a vegetarian or vegan diet that is focused on whole, minimally processed foods.
When I think about a plant-based diet, I'm thinking of any diet that is plant-rich or plant-exclusive that has a focus on whole, minimally, minimally processed plant foods. It doesn't contain a lot of ultra-processed foods, which can also be plant-based, but are not associated with good health outcomes.
Yeah, it depends on what someone's goal is. If someone's just wanting to remove animal foods from an ethical perspective, then they might not have so much focus on the quality of the food that they're eating. Whereas if your goal is to improve your healthspan, how well you're living, how free of disease you are, how long you're living, or both, then the literature is clear, when you're seeing this association between these dietary patterns, have an abundance of plant foods, and good health outcomes, these are dietary patterns that are whole or minimally processed plants and not ultra-processed foods that are plant-based.
The point that you're getting at is a good one in that sometimes there's what's called a halo effect, or health halo. You assume just because a product is gluten free, or high protein, or vegan, because these are often called out on the labels, that it’s healthy. And that's not the case. That's the food industry sort of playing on these buzzwords or keywords. It's more marketing than science.
Mexican.
I mean, usually the big ingredients in any kind of Mexican dish are going to be beans, some avocado, corn, probably some type of grain in there like rice. It could be in a burrito, could be a taco, could just be a plate. Hot sauce? Big fan of hot sauce.
I do love Indian food. And I've spent some time in India. So that's that's up there. You know, Mexican, Indian, and also, believe it or not Japanese.
It's really the flavor. This is a this is the critical point: For anyone who's wanting more plant-based that maybe thinks they're gonna have to sacrifice some flavor or joy. If you think about Japanese food or any cuisine that you like—but let's use Japanese as an example—the flavor is coming from seaweed. It's coming from soy sauce. It's coming from ginger and wasabi. That's the flavor bomb. And really, the fish that’s usually in sashimi and whatnot is more about a texture. If you would just eat that by itself, it doesn't taste like a lot, just similar to if you just cook chicken breast without seasoning and and doing anything to it.
Correct. And so I think often we forget that and I'll get people messaging me saying, “Hey, I want to cook tofu. I really want to enjoy it.” And I say exactly what you just said: then think of it as a flavor vehicle. You need to season it, marinate it, exactly as you would with chicken breast. That usually that lends itself to creating a meal that's much more enjoyable.
I'm training for longevity—that's how I put it at the moment. From a physical capacity to age well, we know that we need good cardiorespiratory health. And in order to achieve that, you need to be doing cardiovascular exercise both at a moderate intensity and high intensity. So I do both of those every week. We know that having strong bones, good bone mineral density, and having good strength is incredibly important as we're aging. Once we get to the age of 50, we're losing bone mineral density, and we're losing muscle mass strength, decade on decade, which can leave us vulnerable to fractures, to falls, to just generally not being able to navigate our environment as much as we would like to.
If you want to be physically able to enjoy your 50s, 60s, 70s, you need to be training in a way that's helping to attenuate some of the bone and muscle strength loss that you get with age. The way that I think about it is like a savings account in your bank. So I'm in my 30s now, but I know that I'm going to have some loss of bone strength in decades to come. So I'm trying to build up that savings so that when I do inevitably lose some of that, I'm still in a place where I can not be at higher risk of falls and fractures, and feel confident doing the things that I want to do.
In my day-to-day, across the week, there's specific strength training. Part of my strength training is a real focus on weight-bearing exercise. So I am loading my skeleton. There's a focus on single leg work. I'm not just doing resistance training on machines where it's all bilateral. I'm doing unilateral exercises that challenge balance. Obviously balance is incredibly important to prevent falls as we age. And then I've got that moderate and high intensity cardiovascular exercise, which is really focused on building aerobic base and metabolic health. And then you're optimizing VO2 max or cardiorespiratory fitness, which we know is very strongly associated with lifespan. So those are the buckets of training that I'm trying to tick off each week.
Yesterday morning, I trained legs. I do a RAMP-style [raise, active, mobilize, potentiate] warm up before I start lifting any weights. That is to get the heart rate up, it's to get some mobility happening. As I get into the first exercise, I'll slowly increase the weight up to working set weight. My goal was yesterday was 16 sets of legs, so I did four exercises, four sets. And I'm training at the moment for strength and hypertrophy, which means muscle growth. And so the rep range that I'm focusing on is between eight to 12 reps for a set.
This is where I think a lot of people get somewhat confused: For a set to be effective, it's not dictated by the number of reps. You could go to the gym—let's just make this easy and pretend we're doing bicep curls—I could pick up a light weight and do 12 reps. And put those weights down versus pick up a weight that's much heavier to do 12 reps and the last few reps I'm really fighting. Those two sets are a very different stimulus. The stimulus is key because that's what causes your body to adapt. So an effective set is when you take that set to within two reps of failure. If you're aiming to do eight or 12 reps, you need to select an appropriate weight such that once you get to a load where you only had two reps left before you were going to be completely at failure and wouldn't be able to lift that weight. So that's what I'm thinking about.
I did Bulgarian split squats to begin with, which is a glute and quad exercise. Then I did leg press. Then I did standing Romanian deadlifts, with dumbbells, which is really more of a hamstring exercise. Then I did lying hamstring curls. Two of those exercises are machine-based: the leg press and hamstring curls. The other two exercises are weight-bearing, which I was speaking to before.
Limp Bizkit. [laughs] Eminem, Limp Bizkit. I need some kind of hype music to really get me into the zone where I can do an effective set, which, back to what I was saying earlier, to get within two reps shy of failure, you're working hard. I can't do podcasts. I love podcasts. I can do podcasts when I'm doing zone 2 training and just sitting on a bicycle. But when I'm lifting weight and really trying to get the body into a place of fatigue, where we'll adapt, and I need something that's hyping me up.
Very little.
Because science, in its essence, is about becoming more certain or reducing uncertainty, but there are no absolutes. And that uncertainty is not what sells, it's not as sexy as being absolute, or going out and telling everyone, “Everything that you've heard or been taught is wrong. I’ve discovered the truths or the answers.” The average person—what happens is we mistakenly think that when a scientist is communicating and has a degree of uncertainty in their language, they're using words like may or perhaps or I don't know, they're untrustworthy.
When I hear those things, I love that. I trust that person. But I think, to the average person out there, as a result of this very clickbait-y environment that we've created and how much we've shortened our attention spans, people hear that and they're not captivated. They feel like that person delivering that that message is not confident, they're not a domain-specific expert. The reason that they feel like that is because they scroll up and then all of a sudden you have this person who is not an expert who is making absolute claims thinks they are captivating, engaging, sexy. It's very hard for the true science or science communicator to compete with that.
[laughs] Where do we start? So this, I mean, the big one, and the obvious one is, there's been fighting for years about low-carb diets, or low-fat diets—what's best for weight loss. And clearly, weight loss, rightly so, is a very important topic. There's a lot of people interested in it, because of increasing prevalence of obesity, and that being a huge if not the major driver of all of these non-communicable diseases like cardiovascular disease, non-alcoholic fatty liver disease, Type 2 diabetes. So within the nutrition sphere, there's been this huge debate between camps: If the government's going to recommend a certain set of dietary guidelines, one camps thinks that it should be low-carb because that's better for weight loss. And then the other side is arguing that low-fat is better. And the ironic thing is that we have enough evidence now to at least partly answer this question. We know that when you match diet quality, and you compare a low-fat diet to a to a low-carb diet, and you get people working with dieticians, and you follow them over a 12-month period, you don't see any difference in average weight loss between these two different ways of eating. What you do see, which is interesting, is that within both groups, some people do well on low fat, some don't. And low carb? Some do well, and some don't. And in both cases, when you go out past five months, people tend to regain quite a bit of the weight that they they lost. So where does that leave us in terms of what advice we can give people? We're not really sure why. It could be social, it could be environmental, it could be the way that their family eats or their friends eat or what's accepted in their culture. So that hasn't been fully elucidated.
But what what I would say to people is focus on diet quality. And the great thing is, you can try one way. And if that leaves you feeling fuller on less calories? Then great. And you're losing weight, great. If not, you might want to try the other one. And so it's good to have options. So that's one big debate. That I don't think should be that controversial anymore. A lot of that debate came from the 1980 guidelines. The US guidelines came out and recommended that people reduce their saturated fat consumption. There's a big group of people who are proponents of low-carb diets that say, “Hey, you know, we came out and we told everyone to eat less saturated fat in 1980. But look what happened. We haven't gotten healthier. It hasn't worked.” I understand that at face value, but the problem is, in nutrition, when you take something out of someone's diet, the effect on their health is determined by not just what you've taken out. But what do they add in. What do they replace it with?
The guidelines, even in 1980, maybe they could have been clearer, but they were pretty clear [about] less emphasis on saturated fat and more emphasis on polyunsaturated fats and unrefined sources of carbohydrates. Now, what actually happened to people's diets is they reduced some of the saturated fat-containing foods, but increased the consumption of foods that are ultra-processed, rich in in refined carbohydrates. And we know that that is not going to really improve someone's overall risk of chronic disease. So what? Well, there's a group of people blaming the dietary guidelines, my position is the guidelines are good. But the problem is people can't follow them. And so the food companies just pivoted in a way to provide low-saturated-fat foods. And this comes back to what we were talking about earlier: just because a food’s low in saturated fat doesn't make it automatically healthy. So that's that's one.
The gluten-free trend. That that was super-popular five or 10 years ago, and I think still is. Certainly people that have celiac, and maybe a very small section of the population who have either wheat allergy or a gluten sensitivity can do better without gluten in their in their diet. But again, when removing gluten-containing foods, what are you eating instead? There are studies showing that people who eat gluten free diets and have a higher risk of cardiovascular disease, and it's probably because they're shifting to gluten-free ultra-processed foods. Fortunately, there are a bunch of whole grains like buckwheat or quinoa or brown rice, for example, that are gluten free. So if someone's removing gluten-containing grains from their diet, ideally, they're replacing them with gluten-free whole grains.
What else? What are the other big debates? I think protein has been a huge debate and remains a huge debate. Source, quantity, timing—all of these things.
I think I think we're probably slightly under-consuming protein. I think if we were to look big picture, though, and say what's driving sarcopenia, the loss of muscle? It's a lack of stimulus. It's a lack of resistance training.
Less than 20% of adults in America are actually meeting and resistance training guidelines, which is only doing two 45 to 60 minutes sessions a week. Without that stimulus, you can have as much protein as you want—you're not going to build muscle. The body responds to that stimulus. And that requires nutrients, especially amino acids, that are building blocks of protein to actually do the recovery, synthesize new proteins, which will help build new muscle tissue and strength. If you look at average protein intakes in America, there are about 1.2 grams per kilogram per day. And we know that even at that level, if you do your resistance training properly, then you can build an incredible amount of strength and muscle.
How I like to frame this: Protein is important, and certainly we can optimize it. But it doesn't matter if you don't get the stimulus in play first. So let's make sure that the general public knows that that is the single most important thing to focus on. Then once you have that in play, we do see that protein intakes up to about 1.6 grams per kilogram seems to be a more optimal intake level than one gram per kilogram. [Approximately .73g, typically rounded to .8g per pound]
You'll hear people push back and say, “Well, high protein is associated with cancer, and mortality.” And what I would say there is that the main study that's cited to provide evidence for that is looking at people who are not metabolically healthy, who are not doing resistance training, they're probably have a very inflammatory environment. And so certainly, if someone's obese, is adding a lot of protein to their diet a good thing? Probably not. But it's a very different context when you take someone who's metabolically healthy, or aiming to be metabolically healthy, and is doing resistance training, and the body is using that protein to remodel skeletal muscle and bone.
The 10 truths is part of the Living Proof Challenge that I created. I've done 300-plus episodes of my podcast, The Proof, now. I've written a book, as you mentioned before. I still get emails and messages every day: “How do I put all this into play? What gives me some sort of streamlined approach is tell me what to do?” So this is my attempt at that. Within the Living Proof challenge, there's really three steps: we're going to test, intervene, and then retest. So it's going to be very objective, we're going to test the things that matter that predict healthspan and longevity, and then we're going to intervene with science-based protocols that we know will improve them. Then we're going to retest. And so testing is where the 10 truths comes in. The 10 truths really are a window into four key systems of the body that influence how well and how long you live. So the musculoskeletal system, cardiovascular system, metabolic health, and psychological. And less than 7% of adults in the US are what would be classified as metabolically healthy—these are people that have diabetes, non-alcoholic fatty liver disease, cardiovascular disease—or they're on the road to it and they don't know.
I believe the answer, short of just going at changing the environment to a Blue Zone environment—[laughs] which I wish we could do—we need to see what's happening on the inside, under the hood, before we develop disease, so that we can course correct. So the 10 truths are a mixture of functional tests and also blood tests that predict healthspan, predict longevity, offer a window into those four key systems. So there are things like Apo B, which is a better predictor of cardiovascular disease than LDL cholesterol, and is now a test that is offered by InsideTracker, who I partnered with to make this challenge possible and zero-cost. Triglycerides, HBA-1C, fasting blood glucose.
There are tests in there that are more specific to the musculoskeletal system: grip strength and bone mineral density as measured by a DEXA scan. Together, what we've done is we have these these 10 different tests that we get people to do. And then from the data we know for that person's age and gender, what is suboptimal, what is normal, and what is optimal? And so we score each of those 10 truths according to that, and then they get a total score out of 10 which we call the longevity score. And then, then they can start the challenge and start implementing the interventions that will affect those 10 truths.
The really interesting thing is—and what I'm hoping that people get out of this, and I know that people that have gone through it are getting out of it—is an understanding of what lifestyle habits affect which biomarker or functional test, because what you might need to focus on is different to what a 50-year-old woman might need to focus on. So we're trying to create some degree of personalization through that. People come into the challenge—it's a 12 week program—they get coaching and emails along the way, and there's an online community. And then at the the end, they go back and do the blood test, again with the InsideTracker tests, and they could put all their results back in and see how that longevity scores changed.
This interview has been edited and condensed.