Prevent cancer by changing your lifestyle

pic source: blog.aicr.org (American Institute for Cancer Research)

There is definitely more to gaining excess body fat than just not being able to fit into your favorite jeans – being obese can also increase your cancer risk. While there are people who have been technically overweight their entire life and are perfectly healthy, becoming obese (BMI>30), especially if that body fat is mostly centered around your abdomen, is a medically defined risk factor for getting certain cancers, among those cancers of the digestive system (oesophagus, colorectum, gall bladder, pancreas), as well as breast cancer (in postmenopausal women), ovarian and kidney cancer. According to the “European Code against Cancer, 4^th edition” [1], about 4-38% of these cancer types can be attributed to obesity. Though these figures might sound grave, there is also good news: losing weight dramatically diminishes cancer risk! However, even if you are at normal weight, healthy diet, active lifestyle and moderate-to-low alcohol consumption are highly advisable as means of cancer prevention. That means, it is totally up to you to decrease your cancer risk.

So what is it about excessive body fat that makes it so dangerous? After all, isn’t it just our energy stores? Not exactly. It has been widely recognized lately that body fat is a metabolically active tissue that produces hormones and cytokines (adipokines and pro-inflammatory cytokines). Increased body fat accumulation can also lead to hormonal imbalances, e.g. insulin resistance. Due to disruption in sex hormone production, obesity can also cause infertility in women (that can be cured by losing weight). Insulin and hyperinsulinaemia can also stimulate cancer cell proliferation and tumor growth. Hyperinsulinaemia can indirectly promote cancer by increasing the circulating levels of insulin-like growth factor 1 (IGF-1), which has been linked to cell proliferation, as well as aging. Leptin, produced by the fat tissue, can also be pro-inflammatory and favor cancer-friendly environment.

So what are the official recommendations of European Code against Cancer? As stated in a recent article (see [1]), they are pretty much common knowledge: don’t smoke, limit your alcohol intake, avoid too much sun exposure, eat a healthy diet, be physically active, try to achieve normal body weight. Last but not least: don’t forget to undergo regular check-ups. Even if you are doing your best to live a healthy life, it does not hurt to pay a visit to the doctor’s office once in a while!

(1) This post is based on the following article:

“European code against cancer 4^th edition: Obesity, body fatness and cancer” by Anderson AS et al in Cancer Epidemiology 2015.

Meal timing: conventional wisdom vs. scientific evidence

picture source: tonictoronto.com

Gone are the times when we, humans, were satisfied with just eating breakfast, lunch and dinner: it’s all about snacking. But we are not only talking unhealthy snacks, such as a doughnut here and there. According to many fitness experts, it is beneficial to eat 5-6 small meals per day vs. 2-3 big meals to “keep your metabolism going”. Thankfully, due to the recent popularity of intermittent fasting (IF), this view is no longer as dominant as it was before, but still it feels like a lot of people didn’t get the memo. Not that everyone should be fasting! But eating 3 meals per day, with at least 4 hours in between, seems to be optimal for keeping your insulin levels from being elevated all the time. At least this is what my intuition is telling me. But is it also true according to science?

There is substantial research on IF and its beneficial effects on health with no caloric restriction. I’ve already mentioned it in one of my previous posts. This makes IF a great tool to add to your toolbox of optimal health, along with a healthy diet, exercise etc.: you don’t have to restrict yourself all the time to reap the benefits of caloric restriction (CR). We are talking, of course, not only about weight loss, but rather anti-neurodegenerative and anti-aging effects of CR. Still, in spite of the fact that substantial scientific evidence suggests that IF has multiple beneficial effects in animal models, proper studies in humans are actually quite few (1). Indeed, it is still a very controversial question whether everyone can benefit from IF or if it can even be dangerous in some cases (e.g., for women). To sum it up, IF has to be enjoyed with caution. What else can you do to keep your insulin levels in check and achieve similar health benefits if you are not exactly ready to fast properly?

Let me introduce you to the scientific concept of time-restricted feeding (TRF).

As I’ve already mentioned, research does not support the concept of eating multiple small meals throughout the day (2). Our ancestors were used to going without food for prolonged periods of time, and so should we. TRF is, in its essence, an inevitable component of any IF regimen, since food is only allowed during a certain time window each day (3). So then, is TRF the same thing as IF under a different name? In a way, yes, however, IF includes protocols that do not allow eating each day, such as alternate day fasting. In contrast, TRF allows ad libitum energy intake during a certain time frame (3), for example, 8-12 h per day, every day. So, in a way, it can be considered a mild IF protocol – you are not allowed to eat during late evening/night and have to keep a certain time window in which no food is allowed.

Both human and animal studies have reported multiple health-boosting effects of TRF.

Animal studies have shown that TRF is associated with body weight loss, improved insulin sensitivity, lower cholesterol levels and reduced levels of pro-inflammatory markers, and all of these results are supported by human studies (3). A recent study using a model organism, the fruit fly Drosophila melanogaster, showed that restricting feeding to a 12h/day period improved sleep and prevented weight gain without caloric restriction in these tiny creatures (5). Moreover, it even protected them against age-related decline in cardiac function. In another animal model, which is closer to humans – the house mouse – TRF also had a profound effect on gut microbiota in mice and prevented weight gain on a high-fat diet (4). More importantly, the same study found that it was protective against diabetes and elevation of total cholesterol levels. The same group of scientists showed, in another study, using different feeding protocols (diets high both in fructose and fat and high in fructose but not fat), that TRF also protects mice from weight gain without affecting caloric intake (like in the fruit fly study), but also reduces body fat accumulation, decreases inflammation, reduces insulin resistance and improves nutrient homeostasis (6). Another remarkable feature of the last study: they tested whether alternating TRF days with ad libitum days produces an effect in terms of decreased weight gain, and it did, meaning if the mice were restricted to a certain feeding window on most days of the week and overindulged at the weekend (sound familiar, anyone?), they still gained much less weight that those mice that were free to eat (a diet high in fat and fructose) whenever they wanted!

So it seems it’s not only important to know what to eat, but also when to eat. Most strikingly, it also seems that if you cannot (for some reason) eat healthy, you have to at least not eat all the time! However, this last point, as all knowledge derived primarily from animal studies, has to be taken into consideration with caution.

Going back to the question whether it is beneficial to eat multiple small meals vs. couple of big meals, many studies, some of them mentioned above, underline the importance of regular meals as circadian pacemakers that set the clock of our metabolism. Therefore, meal timing is definitively a powerful mechanism to not only alter your body composition but to provide certain effects on your metabolism. However, that does not automatically mean that eating many small meals throughout the day speeds up your metabolism in any significant way in the long-term. And why would you want that, anyway? High metabolic rate is unfavorable for survival in animals, and proliferation and growth control pathways are involved in the progression of aging in most species, including humans. Research these days points to dietary interventions that have previously been thought to “lower” metabolism (such as going without food for several hours – which is also not true in the long term, btw) as being beneficial not only in terms of weight loss and body weight maintenance, but also in terms of general health and, very importantly, healthy aging.

So ditch that snacking mentality already! Don’t eat late at night. Don’t eat during the night. Enjoy being free from having to constantly consume food 🙂

1. Horne BD, Muhlestein JB, Anderson JL. Health effects of intermittent fasting: hormesis or harm? A systematic review. Am J Clin Nutr 2015
2. Hutchinson AT, Heilbronn LK. Metabolic impacts of altering meal frequency and timing – Does when we eat matter? Biochimie 2015
3. Rothschild J, Hoddy KK, Jambazian P, Varady KA Time-restricted feeding and risk of metabolic disease: a review of human and animal studies. Nurt Rev 2014
4. Zarrinpar A, Chaix A, Yooseph S, Panda S. Diet and Feeding Pattern Affect the Diurnal Dynamics of the Gut Microbiome. Cell Metab 2014
5. Gill S, Hiep LD, Melkani GC, Panda S. Time-restricted feeding attenuates age-related cardiac decline in Drosophila. Science 2015
6. Chaix A, Zarrinpar A, Miu P, Panda S. Time-Restricted Feeding Is a Preventative and Therapeutic Intervention against Diverse Nutritional Challenges. Cell Metabolism 2014

 

Paleo diet from a scientific perspective

Last week Mark Sisson, my favourite author in the Paleo community, published an overview of scientific literature supporting the health-boosting effects of the Paleo diet, and you can find some of the studies that I found particularly worthy of reading in the “References” at the end of this post. His article made me curious about the origins of the whole Paleo concept. Sure, it is explained thoroughly at each and every Paleo-dedicated website, and I have to say, as a scientist, I do find a lot of sense in the recommendations of the Paleo diet. However, being a scientist also means you have to be skeptical, do your research and, if possible, try to dig deeper – therefore, I decided to go back to the roots and do a bit of literature research on where the Paleo diet came from.

Paleo approach originated as early as in the 70s (not “the latest diet fad”, as viewed by some people) with hands-on studies of Dr. Walter L. Voegtlin, gastroenterologist, who treated some of his patients by recommending them to follow a diet plan, which later came to be known as the Paleo diet. He published his nutritional approach in 1975 in a book called Stone Age Diet: Based on In-Depth Studies of Human Ecology and the Diet of Man. It did take some time for this approach to become popular. 10 years later, an excellent article by Stanley Boyd Eaton, MD, and Melvin Konnor, PhD, was published in the New England Journal of Medicine entitled “Paleolithic Nutrition: A Consideration of Its Nature and Current Implication”. It was their collaborator Loren Cordain who brought Paleo to fame with his popular book “The Paleo Diet”. The rationale behind the concept was the so-called evolutionary discordance hypothesis. To put it in simple terms, it states that there is a mismatch between the way we eat and the way our genes “want” us to eat and this mismatch is at the core of most “diseases of civilization”, such as type 2 diabetes, obesity and (possibly) even neurodegenerative disorders. The authors of the Paleo diet concept (remember: a doctor, an anthropologist and an exercise physiologist, not some self-proclaimed YouTube stars) claim that, according to archaeological and anthropological studies, until 10,000 years ago our ancestors had certain nutritional preferences that they have formed over millions of years of evolution, namely, they ate meat (mostly wild game), a lot of fresh vegetables and fruits, an occasional nut and some fish, too. Then came the dawn of agriculture and the grain- and dairy-based diet. However, our genes have not adapted to these environmental changes as fast as we would want them to. Therefore, a lot of people still suffer from lactose intolerance (although the fact that a lot of us can stomach dairy is a remarkable example of adaptation that did happen in the last 10,000 years!) and not everyone has adapted to a high-carb diet. Of course, I would not go as far as to blame the ongoing obesity epidemic on grains and dairy. (I would blame it on sugar!) Yet a diet composed of lean meats (wild game eaten by our ancestors had a much lower and different fat content compared to our grain-fed animals these days), vegetables, fruits, nuts, seafood and some healthy fats (coconut oil, anyone?) seems like a good way to go, no matter what claims are made for it to be pre-selected for humans by evolution, doesn’t it?

Apparently, not to everyone.

It may be the fact that the Paleo diet has adapted a kind of a cult following (and some of its proponents might seem to act superior to conventional eaters) or the fact that we people like to cling to our guns and won’t give up our breakfast muffins that easily, but there’s been a lot of critique surrounding the Paleo diet lately.

For instance, the British Dietary Association named the Paleo Diet as one of its “Top 5 Worst Celebrity Diets to Avoid in 2015”. Here is what BDA has to say about Paleo: “Jurassic fad!  A diet with fewer processed foods, less sugar and salt is actually a good idea, but unless for medical reason, there is absolutely no need to cut any food group out of your diet.  In fact, by cutting out dairy completely from the diet, without very careful substitution, you could be in danger of compromising your bone health because of a lack of calcium.  An unbalanced, time consuming, socially isolating diet, which this could easily be, is a sure-fire way to develop nutrient deficiencies, which can compromise health and your relationship with food.” (full text here).

Ahem, no offense, BDA, but those claims are complete and utter nonsense. While I would not necessary recommend everyone to cut out food groups (especially if you are one of the lucky guys who are not lactose-intolerant or can stomach beans nicely), but cutting out dairy completely does not necessarily lead to a calcium deficit! There are plenty of plant foods that have a lot more calcium per calorie than milk (hello, kale!). Also, Paleo is far from any kind of diet or lifestyle that might lead to nutritional deficiencies! In fact, there is anthropological evidence that, before the advent of agriculture, people were taller and had no skeletal manifestations of nutritional deficiencies (as reviewed in Boyd Eaton & Konnor’s article from 1985) – how’s that for a calcium deficit? On the other hand, many grains contain anti-nutrients that can mess with vitamin absorption. It is also a completely false assumption that Paleo means you have to eat meat all the time. Actually, our ancestors derived about 50 to 80% of their food from plant sources! And before humans evolved to develop sufficient hunting skills, they were pretty much only eating plant foods. Therefore, vegetables (especially vegetables!) and fruits are supposed the staple of the modern Paleo diet. Eating a variety of plant foods every day can provide you with most of the necessary vitamins and fiber. Even if you miss out on some of them for a few days or weeks – not a problem! Remember: fruits and vegetables used to be seasonal, and certain kinds were only available during very limited periods – that does not mean that human bodies immediately went into deficiency mode!

 So, to sum it up, following a Paleo-style “diet” (I am not a fan of this word, though) seems to be a good way to go and makes sense, since it provides you with all the necessary nutrients, cuts out processed foods and added sugar, encourages high fiber intake (through vegetables & fruits). Now, whether it is true that we must follow Paleo diet rules to be healthy and it is the best kind of diet just because our ancestors ate this way… I am not so sure. After all, we don’t live in the Stone Age anymore, and it does have a lot of benefits, such as dramatically reduced risk of dying from infectious diseases at a young age. The most important thing, after all, is not trying to mimic the exact lifestyle of hunters and gatherers, but rather think rationally and listen to your body. If you have been eating grains your entire life and choose to continue eating them, even though you know that you can get all the necessary fiber and vitamins from vegetables and fruits, that’s totally fine! After all, eating healthy is not just about nutrients, it’s about the whole experience of good food. Most of us can get away with eating a hearty plate of pasta or a mouth-watering chocolate cake from time to time, so what’s the harm in that? I am pretty sure our ancestors would have loved those as much as we do!

References:

1. Frassetto LA, Schloetter M, Mietus-Synder M, et al. Metabolic and physiologic improvements from consuming a paleolithic, hunter-gatherer type diet. Eur J Clin Nutr 2009;63(8):947-955.
2. Jönsson T, Granfeldt Y, Ahrén B, et al. Beneficial effects of a Paleolithic diet on cardiovascular risk factors in type 2 diabetes: a randomized cross-over pilot study. Cardiovasc Diabetol 2009;8:35-49
3. Mellberg C, Sandberg S, Ryberg M, et al. Long-term effects of a Palaeolithic-type diet in obese postmenopausal women: a 2-year randomized trial. Eur J Clin Nutr 2014;68(3):350-357
4. Lindeberg S, Jönsson T, Granfeldt Y, et al. A Palaeolithic diet improves glucose tolerance more than a Mediterranean-like diet in individuals with ischaemic heart disease. Diabetologia 2007;50(9):1795-1807
5. Whalen KA, McCullough M, Flanders DW et al Paleolithic and Mediterranean Diet Pattern Scores and Risk of Incident, Sporadic Colorectal Adenomas. Am.J.Epidemiol. 2014; 180 (11): 1088-1097.
6. Pastore RL, Brooks JT, Carbone JW Paleolithic nutrition improves plasma lipid concentrations of hypercholesterolemic adults to a greater extent than traditional heart-healthy dietary recommendations. Nutrition Res 2015; 35 (6), 474–479

 

Intermittent fasting vs. caloric restriction, v1.0

Caloric restriction (CR) gets a bad rep because of all the crash diets associated with it. However, restricting your calories to 70% of what you would normally consume can boost your brainpower and even delay aging! (1) Another recent study in humans using a similar dietary regimen (30% reduction in calories) found that CR induced dramatic transcriptional changes in skeletal muscle, making the transcriptional profile of older humans more similar to the one of young people (2). CR has the potential to decrease inflammation, increase mitochondrial biogenesis and down-regulate the activity of IGF1/insulin receptor pathway – major aging regulator. Therefore, caloric restriction induces metabolic changes that lead to lifespan extension and improve insulin sensitivity (3).

If CR is, basically, the miracle anti-aging drug we’ve been looking for, why don’t we all just cut our calories? Well, if you’ve never been on a diet before, let me tell you – it’s not that fun. Consistently living on a caloric deficit can make you feel less energetic and cold, never mind the fact that you would actually have to keep track of the calories you consume.

Enter intermittent fasting.

Couple of years ago, fasting was a “no-no” in dieters’ circles. Everyone had heard by that time that fasting could slow down metabolism. Well, apart from the fact that our metabolism is not as much affected by our dietary manipulations as we’d sometimes like it to be (it is, though, I’m not saying it’s not), fasting every once in a while also has major benefits for our bodies. That is why different intermittent fasting regimens are all the rage right now.

Intermittent fasting (IF) is fasting interrupted by eating – or the other way round. In other words, as opposed to long-term fasting regimens, IF protocols can easily be integrated into a normal routine without feeling deprived. The best thing about intermittent fasting is that it can induce similar beneficial changes in your body as CR regimens without actually reducing the number of calories consumed. For instance, IF can reverse negative effects of metabolic syndrome and improve glucose metabolism. Fasting is also beneficial in human diseases with chronic inflammation involvement (such as rheumatoid arthritis, asthma). Fasting can reduce oxidative stress, increase neurotrophic signaling, improve cellular bioenergetics, promote synapse formation and neurogenesis (3). By activating autophagy (a “self-eating” intracellular mechanism which leads to destruction of damaged macromolecules and organelles), fasting shows positive effects in cancer prevention.

There are multiple IF protocols out there, and all of them can be quite effective (fasting 24h once or twice per week, skipping breakfast every day, fasting every other day, eating 1 meal per day and so on). My personal favorite is the Leangains protocol, which basically allows you to eat normally every day – you just have to maintain a 14 (for women) or 16 (men) hour window between your last and your first meal of the day. So you go through an overnight fast (a.k.a. sleep) and then go several additional hours without eating. Drinking black coffee, tea and, of course, water is allowed. If you prefer to have breakfast, you can skip dinner and fast until the next morning.

However, in some cases, fasting can be detrimental. For instanse, women have to enjoy intermittent fasting with a lot of caution or avoid it altogether, especially if they are trying or planning to get pregnant. A widely cited recent study in rats has shown that intermittent fasting can have negative effects on reproduction. While the results from animal studies have to be considered with caution, there is definitely something to think about. Anyway, the overall nutrient status of your diet seems to be much more important than total calories consumed with or without fasting (more on that later). I am not a medical doctor, so I cannot really offer recommendations here, but I would strongly suggest women to be very careful about fasting. I have tried it myself and have seen some benefits in the short-term, however, after a couple weeks of regular 16h fasts I started having troubles falling asleep. I have then read that sleeping problems can be an early sign of elevated cortisol levels, which happens quite often on fasting regimens. So, to sum it up, if you are healthy, not planning to get pregnant and want to try IF – go ahead! But pay very close attention to your body signals. If you notice some sleep problems or something else which seems weird, discontinue immediately!

Most important take-home message: Fasting has to be combined with a nutrient-rich diet, otherwise the benefits will probably not last! Same goes for caloric restriction. Nutrients before calories. Therefore, intermittent fasting can be a nice add-on to an overall healthy lifestyle, but fasting or restricting calories alone is not enough and can even be detrimental for some people. However, if you had to chose between the two regimens (IF vs. life-long caloric restriction), IF regimens are probably much easier to adhere to in the long-term perspective.

References:

1. Witte et al “Caloric restriction improves memory in elderly humans” PNAS 2009
2. Mercken et al „Calorie restriction in humans inhibits the PI3K/AKT pathway and induces a younger transcription profile“ Aging Cell 2013
3. Stranahan & Mattson 2012 „Recruiting adaptive cellular stress responses for successful brain ageing“ Nature Reviews Neuroscience 2012

On finally getting to know yourself

I was planning my next post to be on the benefits of intermittent fasting vs. caloric restriction, but, due to a bout of sudden inspiration I had at the gym, I’ve decided to write about something completely different today. And it is going to be very personal.

In one of my all time favourite comedies, Simon Pegg is faced with a harsh reality of publishing business: once you’re in, you’re only in the first room. You’d have to get to the seventh, if you want to be considered a success and achieve greatness. Well, that pretty much is true for whatever you do in life. However, the definition of greatness can vary. What is the Shagri-La of fitness? Who has been more successful in getting to it: a bodybuilder-slash-fitness maniac with a perfect-looking body, counting each calorie or maniacally hooked on Paleo or someone who is healthy, fit, though imperfect, but mentally stable, eating intuitively when needed and exercising mindfully? For a long time, I thought the first option was the only one worth striving for. Now, I’ve come to emrace the latter. How did it happen?

Well, I’ve come a long way to accept and love myself the way I am. I would actually say, I’m still on my way. I’ve been battling an anxiety disorder my whole life, and I’ve come to realize it just recently. My anxiety has shown its ugly head in multiple ways throughout my life, but its fitness-relevant manifestation started when I was 14 years old. It was then when I suddenly saw myself as fat and disgusting as opposed to  a happy and healthy teenager I actually was.

Me in Japan with my parents when I was 14 yrs old.

It was then when diets entered my life and they never quite left. You name any diet in the book – I’ve tried it. Of course, as you might have guessed, t the end of this journey I was left with bitter regret, health problems and several extra pounds that would not leave my body. Thankfully, this diet craze went into remission for a while when I had entered university at 17 and started to have other things to obsess about. Then, at 23 I moved to Germany, gained a couple extra pounds and, finally, at 26, it all started again. This next time around, however, I did come to realize something very important: I needed to change my lifestyle in a consistent way, if I didn’t want to repeat my mistakes from 10 years ago.

It was then when I started exercising consistently. Fitness entered my life in a completely new perspective, but my mind-set was still focused on the goal, not the process. I’ve started trying on lifestyles, not diets this time. I tried clean eating, I tried fasting, I tried vegetarianism, I tried Paleo. I went from eating pasta to low-carb, from swearing off meat to eating meat every day. Again, I got so caught up in dogmas and restrictions that I completely forgot to actually listen to my body. I gained, I lost – the all too familiar merry-go-round. I was still blaming myself for not sticking to meal plans, exercise plans, for eating too much sugar, for skipping the gym from time to time.

It finally stopped at some point, when I entered that glorious seventh room in my own head.

I have come to realize that I do not need any kind of plans to be healthy. I do not like plans – I enjoy being spontaneous. I cannot follow a plan and not become obsessive about it. I cannot follow a diet or count calories for the very same reason. I’ve read a lot on intuitive eating and it actually does appeal to me very much. However, yet again, I’m not going to adat any kind of eating style. I eat what I want, I exercise because I like it. I only do what makes me happy. If what makes me happy also makes me fit and healthy – hey, that’s just great! I don’t know if you would have come to realize this without going through all the diet madness I’ve been through. Maybe I should have realized it long time ago. It took me 15 years to finally be in peace with myself, and something tells me that this journey of finding peace is not quite over. But it is what it is – a journey. A process of finding oneself is the most glorious, exciting thing in life. Celebrate your own journey!