Lifestyle Medicine, Nutrition

Low carb diets: Are we missing the point?

The recent Lancet study reporting association of increased risk of mortality and low carb diets has stirred up something of a storm among public and healthcare professionals alike.  Publication was swiftly followed by a series of headline-grabbing misinterpretations, coupled with endless pictures of highly refined highly processed carbohydrate based foods – otherwise known as ‘bad carbs’.

Headlines2Somewhere amidst all the hype surrounding what’s good and what’s not (and let’s face it, scare stories sell), we risk missing the point entirely.  The question shouldn’t be about whether carbs collectively are good or bad.  The real question should be whether we are consuming good quality carbs and avoiding bad quality carbs.  The Lancet study looked at carbs as a whole – lumping consumption of highly processed and refined white bread, pasta, cakes and biscuits in the same category as healthy natural wholegrains, vegetables and fruits.  In which case, how do we know what those in the ‘low carb’ group were really eating?  How do we know they weren’t all eating relatively low quantities of healthy vegetables, fruits and wholegrains, and relatively high quantities of commercially produced bread, pasta, cakes and biscuits?  We don’t.  Because this data wasn’t actually published.  What’s more, the ‘low carb’ groups that provided the analysis for plant versus animal protein outcomes comprised a carbohydrate intake of average 38%.  This is not low carb.  That aside, observational studies such as this are subject to distortion by unexamined confounding factors.  This means we can’t draw any real conclusions about cause and effect.

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These factors combined make this study flawed to say the least.  Yet, sadly, the harm is done once the headline hits the press.  How many people will actually gather the ways and means of reading and analysing the raw data and drawing their own conclusions?  How many would even consider doubting the results of a study from such a prestigious journal as the Lancet?

Study design aside, the big problem with the media portrayal of nutrition studies in general is that they tend to encourage avoidance of entire food groups, regardless of quality.  Focusing on food groups misses the point entirely.  We don’t eat macronutrients.  We eat food.  Imagine a restaurant menu offering only varying quantities of carbohydrate, protein and fat.  Not exactly appetising is it?  Food is so much more than just the sum of its parts.  Food is meant to be savoured and enjoyed, in its natural form.

Low fat marketingThe food frenzy of the past few decades has been the low fat diet, a movement that gained momentum in the early eighties when adopted by UK national dietary guidelines.  The British media were quick to jump on the bandwagon, along with the food industry.  This hype has somehow managed to con generations of western consumers into eating high quantities of highly processed, highly refined, high carb, ‘low fat’ foods, despite no original supporting RCT evidence demonstrating reduced risk of all-cause mortality from reduced fat in the diet [1].  We’re now facing an epidemic of diabetes and obesity.  And so manifests the new ‘enemy’: carbs. Which includes highly processed and refined carbs (the real enemy).

Not great news for a food industry that made billions from the low fat craze.  The result?  Frantic mass-marketing of highly processed and refined protein bars and ‘low carb‘ snacks.  The food industry can breathe a sigh of relief while future generations succumb to the health consequences of various micronutrient deficiencies and digestive disorders for years to come.

The real problem

Headlines1Western diets have become increasingly energy dense and nutrient deplete, despite good value nutritious food being more available to us than ever before.  What’s changed?  Choice.  We now have more choice than ever before.  But more choice leaves us open to poor choice.  With this almost limitless choice on offer, it’s more important than ever that we receive proper education about what constitutes good food, be wary of mass media scaremongering and food industry marketing, and make sensible healthful food choices.

A myriad of guidelines worldwide all express their own differing recommendations for a healthy diet.  That’s before even considering the regular headline grabbers offering their twopence worth.  Often the information offered is confusing and contradictory.  Little wonder we lose interest.  Nutrition in the modern world has become a minefield.

What do our bodies really need?

jacob-postuma-409825Our bodies need energy in order to survive.  But more than that, in order to actually thrive, we need good quality whole foods that contain plenty of vitamins and minerals.  We gain our energy from nutrients in food, in varying quantities, depending on our individual and cultural eating habits.  Nutrients are comprised of macronutrients (carbohydrate, protein, fat) and micronutrients (vitamins and minerals).  It is the combination of high quality macro and micro nutrients, derived from whole foods, acting in synergy, that allows us to perform at our best, both mentally and physically.  It’s not about demonizing food groups, but enjoying good quality and delicious whole foods.

What is carbohydrate?

Carbohydrate is a macronutrient.  This means it’s a source of energy, typically consumed in gram rather than milligram quantities.  Other macronutrients are protein and fat.  Carbohydrate is composed of three key elements, in varying structural forms.

At their simplest, carbohydrates consist of three single units (glucose, fructose, galactose), which combine in various combinations of pairs to produce what we know as sugars (sucrose, maltose, lactose), and in varying repetitions of single and branched chains to produce what we know as oligosaccharides (found in vegetables such as artichoke, chicory, asparagus, onion, & leeks) and polysaccharides (found in all other vegetables, fruits, and grains).  In their natural form, carbohydrates are a valuable source of energy, as well as providing us with essential health-boosting micronutrients, phytochemicals, and fibre.

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Carbohydrate is broken down into glucose in the body, which in turn provides our brain and red blood cells with essential energy.  Good quality carbs are non-refined, and include leafy vegetables, root vegetables, fruits, nuts, seeds, legumes, and healthy wholegrains.  Poor quality carbs are those that are highly processed and refined, such as commercially produced sliced bread, pasta, white rice, cereals, cakes and biscuits.

What are wholegrains?

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The term wholegrain means the original grains retain their inner and outer parts – the germ and the bran.  These contain all the goodness – fibre, vitamins, minerals, and antioxidants.  Fibre aids digestive transit and can help lower cholesterol.  Vitamins and minerals support numerous metabolic and physiological functions.  Antioxidants defend against harmful molecules called free radicals, which can damage the cells of our body.

  • Wholegrains include whole oats, brown rice, quinoa, millet, wheat berries, cracked wheat, bulgur, barley and rye. Most commercially produced breads, even those marketed as ‘wholemeal’ or ‘wholegrain’, do not count as wholegrain.
  • Consuming healthy wholegrains may lead to numerous long term health benefits, including reduced risk of heart disease, stroke [2], colorectal cancer [3], cardiovascular disease, cancer, and all-cause mortality [4][5][6] .
  • Refined carbohydrates, such as white bread, white rice and pasta, are not wholegrains.  They contain only the middle endosperm layer of the grain. This is devoid of all the goodness in the grain – the micronutrients, antioxidants and fibre.
  • Refined carbohydrates also tend to have a higher glycaemic index, which means they produce higher amounts of glucose in the bloodstream two hours after eating.

Why do good quality carbs matter?

Poor quality carbs provide us with a whole lot of glucose and not much else.  But good quality wholefood sources of carbs give us so much more than this.  Good quality carbs also provide a number of essential health boosting components, micronutrients and phytochemicals, including:

Vitamin C:

  • Important for collagen synthesis, wound healing, immune function, iron absorption, and provision of antioxidant activity.

B Vitamins:

  • Collectively important for the production of DNA, metabolism of carbohydrates, fats and proteins, production of ATP (energy), synthesis of neurotransmitters, synthesis of red blood cells, and normal cell division.
  • Vitamin B9 (Folic acid) helps prevent neural tube defects.

Carotenoids, including: 

  • Beta carotene: Precursor to Vitamin A, important for vision, immune function, skin health and gene transcription.
  • Lutein: May help slow progression of age related macular degeneration (ARMD).

Fibre:

  • Soluble fibre feeds healthy gut bacteria, helps maintain gut transit and prevent constipation.
  • Regular consumption of fibre rich foods may also help with weight loss, reducing cholesterol, and lowering colorectal cancer risk.

So cutting out or drastically reducing carbohydrate intake risks missing out a wide variety of important dietary components vital for maintaining long term health and well-being.

So what should we all be eating?

One of the best dietary guides I have seen comes from the British Association for Nutrition and Lifestyle Medicine (BANT).  The guide highlights the importance of healthy sources of carbohydrate, among other lifestyle factors conducive to achieving and maintaining good health:

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1. Eat plenty of leafy / non starchy vegetables and some fruit

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  • Aim for at least 5 portions of different vegetables per day and 1-3 portions of fruit. A portion of vegetables equates to about 3 heaped tablespoons.  For fruit, a portion is a single piece of fruit / handful of berries.  Avoid juices and smoothies – they tend to be a concentrated source of glucose and may lack the health benefits of added fibre found in intact whole fruits.
  • Eating a variety of vegetables has countless benefits. They contain plenty of fibre, which in its soluble form can lower cholesterol and blood glucose, as well as aiding digestive transit.  They are also a valuable source of essential vitamins and minerals, vital for optimum physiological function and prevention of some deficiency associated diseases.
  • There are so many delicious fruits and vegetables available to us. Try to aim for a variety of colours.

 

2. Replace bread & pasta with wholegrains and root vegetables 

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3. Include dairy or alternatives as important sources of calcium, as well as additional sources of protein.

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  • Calcium is essential for teeth and bone health and plays a role in muscle and nervous system function.
  • Non-dairy sources of calcium include leafy green vegetables, tinned fish (bones included), seaweed, almonds, and eggs.
  • Dairy sources of calcium include whole milk, whole yoghurt, and cheese.

 

4. Eat healthy fats

healthy fats

  • Fats must be consumed in the diet for provision of essential fatty acids, such as omega-3 and omega-6, which cannot be made by the body.
  • It’s a myth that fats are unhealthy. Consumed in moderation and as part of a balanced diet, natural fats are healthful, nutritious and tasty.  Fatty acids are vital not only as a valuable source of energy, but for insulation, hormone synthesis, cell membrane integrity, and facilitating absorption of fat soluble vitamins.  Fat soluble vitamins are essential for numerous physiological functions, including vision, immunity, antioxidant capacity, blood clotting, bone health and cell growth.
  • Aim to include plenty of omega 3 sources in your diet (including oily fish, walnuts, flaxseed, chia seeds, and cod liver oil).

Take home message

Our bodies need non-refined, minimally processed carbohydrate, natural sources of protein and natural sources of fat.  Eaten in balance and in moderation.  Our bodies do not need packaged processed refined foods, dietary scare stories, avoidance of entire food groups, or extreme diets.  This may not be the attention-grabbing stuff of front page news, but it’s certainly a message we could all do with hearing a little more often.

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