Will that high protein diet kill you?

After last Tuesday’s television show ‘how not to get cancer’ I got a number of concerned emails and Facebook messages from people questioning their protein intake. Specifically,  information that a high protein diet increases health risk and mortality. As a nutritionist who advocates a higher protein load, here’s what I’ve read about the role of protein and disease, as written by people much smarter than I am:

Information regarding health risks associated with a high protein intake has been critically reviewed by experts in the field, specifically the way the population dietary data from the National Health and Nutrition Examination Studies (NHANES) was analysed to determine that higher levels of protein increase overall health risk. The major criticisms were:

  • They eliminated half of the data points with no explanation;
  • Their definition of low protein (below 10%) should in fact be labelled as ‘inadequate protein’ as defined by the Institute of Medicine (IOM) protein ranges (10-35% of dietary energy), and in New Zealand adequate protein is 15-25% of energy in diet. The arbitrary cut-off used by the authors meant less than 450 people fell into the ‘low protein’ group;
  • The population data gathered dietary information via a single 24-hour diet recall once in an 18-year period; and
  • Body weight or body mass index (BMI) was not reported – given the clear association between excess body fat and chronic disease such as cancer, cardiovascular disease etc, this was a massive oversight.

While the paper outlined in the review also looked at laboratory trials, these were based on rodent studies and not clinical trials in humans. Differences in metabolic rate, the way we utilise nutrients and digestive tracts (the rodents more able to handle fibrous foods than ours) means that, despite interesting findings, we cannot conflate the findings here to humans, as they are not directly transferable.

Other points to note regarding research suggesting that a lower protein diet is good for longevity:

  • Many of the studies are based on rodent studies (not humans) and, in addition to what I posted above, the type of protein studied is typically casein – a dairy protein that has more potential to be inflammatory and one rodents are not naturally adapted to consume;
  • High amounts of dairy protein have been found to increase insulin, triglycerides and result in excess body fat compared to other sources of protein provided to the rodents;
  • Much of the research also show that it could be an effect of a high methionine intake which – when not balanced with other amino acids such as gelatin) for some people, can build up the amount of homocysteine (another amino acid) that increases risk of cardiovascular disease;
  • As we age, we are at greater risk of sarcopenia, dyopenia and poor health due to falls if we don’t have a decent amount of muscle mass, which requires protein to help lay down this muscle;
  • The majority of studies point to a higher protein intake being protective for quality of life as we age, not detrimental; and
  • We become more anabolic resistant as we age, meaning we are unable to lay down muscle the way we are when we are younger to the same extent. This could be as a result of both inactivity and lower levels of oestrogen and testosterone, meaning the a higher protein intake is required (in addition to resistance training).

And here is what I know regarding a low protein diet in the real-world setting:

  1. People are hungry. Women, especially, struggle to eat an appropriate amount of food when they restrict protein. This restriction (intentional or otherwise) leads to poor blood sugar control, poor appetite control and mood problems (either low mood or increased anxiety).
  2. People can only restrict for so long until it backfires. A lower protein intake might be totally fine on a Monday, things are okay on a Tuesday, but by Wednesday people are climbing the walls looking for something to eat. Or, for some, this process happens across the course of a day. This means that despite having a decent amount of food at dinner, the undereating of protein across the day leaves you standing in the kitchen at 8pm looking for something to eat and wondering why you are not hungry, but just ‘not satisfied’.
  3. Practically speaking, when you restrict protein, what is there left to eat? Carbohydrate. We eat until our minimum requirement for protein is filled and, in the absence of quality protein sources we will overeat on calories (specifically carbohydrate calories) until this requirement is met. For many, this results in poor nutrient status, poor blood sugar control and excess body fat. It’s these three things which have consistently been found to result in increased risk of metabolic disease and cancer, not the protein load.
  4. People (generally speaking) fare best when we base their meals around protein and then toggle the fat and carbohydrate around that, based on their body composition and their activity levels. For many, this is more than a palm sized serve at each meal, and across the course of the day, for most people, this is at least 100g of protein from foods that are quality protein foods. In New Zealand, we get most of our protein (according to the most recent nutrition survey – which is 10 years old, actually) from bread. Bread! Wheat derived protein is one of the lower quality sources we can eat, with the amino acids not being as easy to digest and assimilate as those from animal-based sources.

So, clinically I am not at all concerned about advocating a moderate-high protein load for most people, and the television show last Tuesday did nothing to change my view on it. A longevity diet approach which is low in protein looks promising for a week a few times a year to confer benefits of fasting related to lifespan, but in terms of a day-to-day diet it will likely leave you frail, hungry and irritable. There is not enough human data to show that this approach will lead to a longer life, but I gotta say, it doesn’t sound like an enjoyable way to live beyond 100 years. Most evidence points to muscle mass being extremely important as we age to maintain quality of life and health span. This requires adequate protein and resistance training. In the words of Robb Wolf (as said on a recent podcast), we need to “eat and move in a way that lays down as much muscle as we can now, and then fight like the devil to keep it”.


A good source of protein, and pretty delicious (PC: healthline.com)

Starving? Read this and you won’t be.

One of the biggest downfalls I see with diet is the lack of protein across the course of the day. A typical pattern I see when I talk to people about their food intake and their appetite is:

“I’m ‘good’ all day, but can’t control myself come 5pm”


“I’m fine all day, but after dinner regardless of how full I feel, I’m not ‘satisfied’ ”


“I’m ‘good’ till Wednesday then it’s all downhill from there”

Any of this ring true? The reason I bring this up is that many people report being absolutely starving, constantly thinking about their next meal and (more often than not) their frustration with being unable to lose body fat as they view their diet as being pretty good. When we delve further, I see quite clearly that when people are “good” it generally means they are undereating during the day, and this leads to almost a binge-like pattern later in the evening, or just an inability to stop snacking. A typical pattern might be:

  • Breakfast: cereal + fruit + trim milk (cos, you know, fat is bad)
  • MT piece of fruit/trim latte OR nothing
  • Lunch: chicken salad perhaps 50g chicken, no-fat dressing, no carbs (hey, we got rid of them back in the 90s!)
  • AT: nothing, or a carrot or similar
  • 5pm: a small handful of nuts, then a slightly larger one.
  • 13pm: a carrot. And hummus
  • 21pm: a few spoons of PB,
  • 47pm: cheese while making dinner
  • 10pm: leftovers off the kids plate,
  • 32pm: dinner (full!)
  • 20pm: piece dark chocolate
  • 35pm: bite of icecream *well I’ve blown it now*
  • 40pm: bowl of icecream *I’ll be better tomorrow*
  • 10pm: 3 rows of chocolate…..

Does this look familiar? While they may be low calorie/fat/carb during the day, people with this dietary pattern will generally consume more calories than they realise in that pre-post dinner window. This isn’t just about calories and fat loss though. Many people also suffer from anxiety around their food intake, gut or digestive issues from consuming more food than what is comfortable, sleep issues due to an excess of food close to bedtime, and unhelpful self-talk related to their perceived lack of control. This last point can be particularly damaging to long term success, as for some this can perpetuate feelings of failure and subsequent behaviours which make it difficult to change in the long term. Other long term consequences of a low protein and low dietary energy early in the day include reduced muscle mass, reduced metabolic rate, low mood and a greater propensity for fat gain in the long run.

How to prevent this?

Eat more protein at the start of the day – it is more satisfying and is digested a LOT slower than other nutrients, and will prevent overeating later in the day. What you eat at the start of the day really impacts how you feel and what you eat at the end of the day. Many experts in the field of protein research view 0.8-0.9g protein per kilogram of bodyweight, based on nitrogen balance studies, are likely underestimating overall protein requirements. This is especially true for those in the older age bracket and for people wanting to drop body fat where studies such as this have found that 2.4g protein per kg bodyweight can help maintain metabolic rate and protect muscle mass. Clinically (which, to my mind, is as important as what the literature says), very few of my clients thrive on a lower protein diet. Athletes (FYI) are recommended around 1.7-2.2g per kg bodyweight and in general a higher protein intake will benefit mood, sleep, blood sugar and appetite.

So what does 2.4g per kilogram look like for the myriad of people out there wanting to drop body fat? IE if you weigh 75kg, your protein intake should be around 180g. If we consider the standard protein sources available, then it might look a little like this (amount of protein in brackets):

  • Breakfast: 4 eggs (29.2g) – with vegetables, scrambled, cooked in butter, coconut oil or olive oil
  • Lunch: Medium chicken thigh 146g (34g), sliced up into salad with olive oil dressing and lemon
  • AT: ½ cup of cottage cheese (18g) with pesto mixed through
  • Dinner: Medium steak (186g) with roast vegetables 57.3g

Well, that is 139.4g of protein per day, around 1.86g per kilogram body weight, leaving an additional 40g of protein being derived from plant sources. You can see that you have to eat a lot of food to get your protein in – which is completely different from the ‘being good’ scenario above.

While the run down of foods to eat above may freak you out if you’re used to a cereal and salad diet – don’t be scared. If your dietary pattern looks much as I described above, allowing more protein earlier in the day will have a huge influence on your overall intake – the pattern of grazing late afternoon into the evening will change. I promise. I’ve written about the protein leverage theory before when discussing the National Heart Foundation’s food guidance system (click here for that post) – that the body has an innate requirement for protein and will drive appetite until this is requirement is met. If you eat a lower protein diet, research suggests you may eat more overall calories (and calories from refined carbohydrate) compared to people consuming a moderate protein diet. I know many people don’t like eating more food earlier as they don’t believe they have the willpower to stop. I recently wrote about the main physiological driver of ‘lack of willpower’, and eating more protein will kill this response pretty quick. You just have to try it. When combined with fibre, a bit of fat and carbohydrate that takes longer to digest, protein is (to my mind) the nutrient to focus on for controlling appetite, hunger levels and helping maintain an optimal body composition.

Protein quality definitely counts here too. This measure has been revised recently to reflect updated knowledge regarding the digestibility of protein, however regardless of technique used to establish bioavailability of protein source, animal protein consistently scores higher than plant protein in terms of protein quality (with 0.75 as a cut-off for good digestibility – see here for some food-based tables). This will have implications for their effect on appetite (i.e. ability to keep you satisfied). In part this is due to the presence of anti-nutritive factors in plant based proteins (such as lecthins, tannins, phytates etc) that prevent our absorption of them (see here for a comprehensive report on the digestibility of protein). This is not to say that plant protein doesn’t count. I have many clients who are vegetarian and, for them we ensure a good intake of eggs, cheese and protein powder (whey, pea or egg white protein powder for a good variety). People following a vegan diet are a little more challenged. While they will get protein from legumes, nuts, edamame beans, tempeh and seeds, I recommend (again) protein powders, and incorporating a variety of these (such as pea, hemp and sacha incha) in their daily diet. These are lower in overall protein compared to, say, whey (sacha incha has around 12g per 20g serve (60% protein), compared to whey protein (17-18g, or 85-90%). But if we are looking to increase protein across the course of the day, these will certainly be useful.

So…what about you?

If you’re a numbers person, think about your goals (weight loss, muscle maintenance etc) and shoot for the grams per protein I’ve mentioned above. Use Easy Diet Diary, My Net Diary, Fat Secret or Cronometer to find out how much protein is in the foods that you’re eating, and what the distribution of it is across the course of the day. Then use the information provided to plan for a higher protein intake and a more even distribution. At the very least, aim for around 25-30g of protein in your meals. If you’re not a numbers person, then use tables like these to give you an indication of where protein is in food. Aiming for:

  • 3-4 eggs at breakfast, or 120g protein-based food or 1-2 fist-sized worth; and
  • at least 120-150g of protein-based food at lunch (or 1-2 fist-sized); and closer to
  • 160-200g protein-based food at dinner (or 1-2 fist-sized); and

shooting for the higher numbers the more active or the bigger you are and THEN base the remainder of your macronutrient intake (carbohydrate and fat) around this – and don’t forget the abundance of non-starchy vegetables. If you want some help with this, get into contact with me or sign up for my online nutrition coaching – this is pretty much how I build my meals. While initially you may feel hungry, this will likely be habit rather than actual hunger (or a hormonal response, as your body’s appetite hormones work on a circadian rhythm and ghrelin may well be released as your body is used to eating at that time. Brushing your teeth is one of the best things to do to cut that hunger. If you wait it out, it will eventually pass and you’ll easily eradicate the feeling of hunger, the grazing later in the day and regain the feeling of control around your food (rather than letting the food control you).


Thankfully, it hasn’t come to this. There is an easier way to control your appetite… (PC healthycompare.com/diet-pills)

Feeling SAD?

Damn. We Aucklanders are getting our share of terrible weather. That’s the problem with being smug and posting pictures of our awesome non-winter winter climate… eventually it comes back to bite us in the butt. Usually in spectacular fashion: this week has been almost torrential storm-like conditions, with power outages and garden furniture strewn across the driveway (or is that just me?) Naturally this dip in temperature to below 15 degrees comes with it a sense of gloom as the sun fails to make an appearance. Grey clouds are oppressive, huh? Does that make you feel a bit blue? It does me – once the temperature drops and I haven’t seen the sun in four days I feel utterly miserable, diagnose myself with mild depression, and more specifically Seasonal Affective Disorder – or SAD. It’s a particular type of depression that starts in the autumn and doesn’t let up until the daffodils are out. In reality, I don’t think I would be diagnosed with SAD, and population prevalence is in the realm of 1-12% depending on your location, a higher prevalence in areas with longer winter days and lack of sunlight hours (one reason why I couldn’t live in ‘middle England’; not only does it sound horribly dull (it’s up there with ‘original flavour’) but daylight hours are limited during winter. And I know it’s worse elsewhere). But I digress. However, I feel a bit blue all the same.

Interestingly, there are two types of seasonal affective disorders – some curious people feel more depressed in summer than they do in winter, therefore the reverse is true. That to me is like a fate worse than death, quite frankly. Up there with Man Flu. SAD is diagnosed by the presence of symptoms such as: 

  • Decreased energy levels
  • Difficulty concentrating
  • Fatigue
  • Increase in appetite
  • Increased desire to be alone
  • Increased need for sleep
  • Increased irritability
  • Increased anxiety
  • Weight gain

Scientists have pinpointed a few reasons why the lack of sunlight can disrupt our mood. This is largely due to our levels of melatonin – this is a hormone which plays a role in how our body regulates its sleep/wake cycle. The longer periods of darkness in the winter months may stimulate melotonin production and potentially people with SAD overproduce melatonin or are hypersensitive to melatonin in the winter months. While melatonin is recommended on an infrequent basis for people who struggle with sleep (for example, during periods of travel where jetlag can set it), too much melatonin can result in headaches, day time sleepiness, and depression.

Other evidence shows that decreased levels of neurotransmitters (chemicals that transmit signals between nerve cells) such as serotonin or dopamine may also play a role in triggering SAD. Low levels of serotonin in particular have been associated with carbohydrate cravings in people with SAD, and with sleep disorders and depression in the population at large. So not only does the reduced amount of serotonin trigger carbohydrate cravings (carbohydrate facilities the production of serotonin), this subsequent increase in food intake can lead to weight gain and further feelings of despair. Lose-lose, really. Even in those that don’t feel particularly blue during winter, the stodgy, starchy carbohydrates that can lead to weight gain and increased carbohydrate cravings are the warming foods we naturally gravitate towards.

As serotonin is largely produced in the gut I went searching for studies that looked for a link between digestion and SAD, as without the nutrients required to produce serotonin – including tryptohan which is an amino acid and key in the process – levels will be lower. I didn’t come up with any though, but with the clear link between the gut and brain, it makes sense that there would be.

Lastly I also found interesting relationships between SAD and other conditions. It’s not just weight gain that could be a problem – A Finnish study found there was a significant association between seasonal changes in mood and behaviour and metabolic syndrome, with risk of metabolic syndrome increased by 56% in those with seasonal affective disorder. The researchers noted that the metabolic syndrome is related to changes in the circadian rhythm – and that circadian, sleep-wake and seasonal cycles may each be regarded to reflect an intrinsic metabolic cycle. Sleep onset is a switch for the metabolic and cell repair systems from daytime to night-time settings and if the right signals aren’t there, the circadian clockwork relies more on the metabolic cycles producing time-giving signals needed for adaptation – insulin plays a role in this and helps set the circadian rhythm.

So what treatments exist for helping improve melatonin and serotonin levels and hopefully offset the low level depression that many people experience?

Light therapy: helps with regulating melatonin production and can indirectly affect serotonin levels by blocking the mood-lowering affects of acute tryptophan depetion. exposure to intense light in the early morning has been found to be most effective, as this suppresses melatonin. The treatment involves sitting in front of fluroscent lights which are installed behind a diffusion screen, and carrying out normal activities for anywhere from 30 min to 2 hours depending on the intensity of lights. The critical factor is that the light matches that of either early morning or just before sunset. he dosage most often found to be effective is 5,000 lux per day, given as 2,500 lux for two hours or 10,000 lux for 30 minutes. This isn’t just sitting in front of a desk lamp.

I talk about sleep all the time… but in addition to adequate sleep, getting up and going to bed at around the same time most days can also help regulate levels of melatonin, particularly combined with the light therapy as above.

Get outside and exercise: it might be the last thing you feel like doing but honestly – nothing is as energising and invigorating as getting outdoors, particularly in cold, windy, inclement weather. This helps boost serotonin levels by increasing availability of tryptophan to the brain. This is particularly important as we tend to spend a lot of time inside. The added bonus here is getting natural light – this helps boost overall mood.

Fight against the desire to stay at home and make plans with friends or family. It’s all too easy to hibernate, inevitably making you feel worse.

Diet: while there are foods that are high in serotonin or tryptophan, few actually cross the blood brain barrier to enable their action in the body to improve mood. Typically high protein foods containing tryptophan were recommended, though this doesn’t actually increase serotonin levels in the brain when studied  , as amino acids compete for transportation in the body and most protein containing foods are relatively lower in tryptophan than other amino acids. Hence perhaps changing the ratio of tryptophan to other amino acids is useful, and research has shown that supplementing with a dietary protein alpha-lactalbumin (a constituent of milk) can increase serotonin through this strategy. While interesting, it’s not very practical for people in every day life. Insulin helps set the circadian rhythm and perhaps a diet that focuses on high protein for breakfast and lunch, with small amounts of carbohydrate at night can maximise insulin secretion at night and help appropriately reset circadian rhythm. Unsurprisingly, the importance of a whole food diet rich in nutrients to support digestion and absorption of nutrients cannot be overstated given the link between serotonin and mood.

Oh, and hopefully the increased protein, the exercise and the sleep helps you combat those carbohydrate cravings. In addition to this, find some equally warming winter substitutes. It’s not like you need to completely avoid carbohydrates at all (see above re insulin) – it’s about avoiding Richard Dreyfuss amounts of the white stuff. That’s not going to make you feel any better I promise.

  • Mash: cauliflower mashed with butter or olive oil, herbs and seasoning.
  • Fries: slice swede and boil until a little bit soft. Dry off and coat in coconut oil and some almond flour and roast. Or just roast from raw.
  • Pasta: zucchini noodles (or as my friend Helen likes to call them: courgetti) or use leeks (cook)
  • Rice; cauliflower rice

There are certainly people who are diagnosed with SAD, and equally there are people (like me) who wouldn’t meet the diagnostic criteria yet still feel a bit less awesome. All of the above tips then will help you keep feeling awesome over the winter months. And we are almost half way through! That’s enough to make me feel happier :-).