Low carb déjà vu

Every now and again, something happens that makes me realise I live in a bubble. You see, for over 25 years, I’ve been completely immersed in the study of human physiology, nutritional biochemistry, therapeutic nutrition, sleep, exercise, psychology and pretty much everything else that relates to helping human beings become healthier and happier.

Nerding out on the latest research leaves no time (or interest) for watching TV or paying attention to my social media feed. So I’m blissfully ignorant of what the average Joe or Josephine is exposed to when they watch the news or scroll through Facebook – except when clients or EmpowerEd members ask my opinion of the latest fad diet they’ve had thrust across their feed.

And suddenly it hits me: the rest of the world has no idea what I know, and because they don’t, they can easily be snowed by fake-tanned celebrity chefs, journalists who fancy themselves as scientists, and YouTubers with zero qualifications who label themselves as ‘wellness experts’.

As a case in point, the number of clients I’ve seen who’ve been suckered into the low-carbohydrate diet fraud is astonishing – and when you’re familiar with the research on the dangers of this way of eating, truly terrifying.

I’ve written before about low-carb diets in my article Eating low-carb? Get your facts straight – your life depends on it! but with the flurry of newer research on the health effects of restricting carbohydrates, I figured it was time for an update. Here’s the latest:

Overwhelming evidence that low-carb = early death

A systematic review and meta-analysis of 17 studies found that eating a low-carb diet raises the risk of all-cause mortality by an average of 30%, which means you have nearly a one-third higher risk of dying from any cause if you cut carbs. If you think that’s shocking, one study included in the review found a twenty five times higher risk of all-cause mortality in low-carbers.

The authors concluded that

“These findings support the hypothesis that the short-term benefits of low-carbohydrate diets for weight loss are potentially irrelevant.”

In other words, the goal is not to be the skinniest corpse in the morgue; it’s to figure out the best way to eat in order to live a long, healthy life.

It doesn’t matter where you live or how old you are, eating low-carb will shorten your life

A study of 42 237 Swedish women aged 30-49 at baseline, who were meticulously tracked for 12 years as part of The Women’s Lifestyle and Health cohort study, found that either decreasing carbohydrate intake or increasing protein intake raised the risk of death, especially from cardiovascular causes, with the combination of the two being even more hazardous.

Among 924 elderly Swedish men, those who ate a low-carb diet were 19% more likely to die of any cause, and 44% more likely to die of  cardiovascular disease. On the other hand, a more Mediterranean diet pattern – which by definition includes ample carbohydrates from whole plant foods – lowered both all-case and cardiovascular mortality.

In a cohort of nearly 23 000 Greek adults, all of whom were healthy at the beginning of the 10-year study, higher intake of carbohydrates was associated with significant reduction of total mortality, whereas a low carb-high protein diet raised the risk of total, cardiovascular and cancer mortality.

Low-carb is especially dangerous if you’ve already had a heart attack

The long-running Nurses’ Health Study and Health Professional Follow-Up Study examined the dietary habits of 2258 women and 1840 men both before and after they survived a first heart attack, and found that eating a low-carb diet high in animal protein and fat raised the risk of dying of any cause by 33%, and dying from a cardiovascular cause (such as a second heart attack) by 51%.

Upping one’s intake of animal foods after a first heart attack raised the risk of dying of cardiovascular disease even more.

Those who ate a plant-based low-carb diet did not suffer any increase in the risk of dying, but they didn’t experience any benefit either.

Diabetics raise their risk of coronary heart disease if they eat low-carb

A study comparing biomarkers in 571 type 1 diabetics – who are at a dramatically higher risk than non-diabetics of developing coronary heart disease (CHD) – and 696 non-diabetics, none of whom had any symptoms of CHD, found that the diabetics ate more fat, saturated fat and protein, and less carbohydrates, than the controls.

Contrary to the marketing pitch of low-carbers who claim that diabetes is caused by those evil carbs and we should be hoeing into animal foods and ‘healthy fats’ to prevent or treat it, the higher the intake of total fat, saturated fat and monounsaturated fat in both diabetics and non-diabetics, the higher the level of CHD risk factors including

  • Total and LDL-cholesterol
  • Non-HDL cholesterol (i.e. all dangerous cholesterol subfractions)
  • Apolipoprotein-B
  • HbA1c (a reflection of average blood sugar levels over the previous 3 months)
  • Body mass index
  • Intra-abdominal fat (belly fat)
  • Waist circumference and
  • Diastolic blood pressure
  • BP;

and the lower the estimated glucose disposal rate (EGDR), a measure of insulin sensitivity in type 1 diabetics. Higher intake of trans fats and polyunsaturated fats also correlated with all of these risk factors except for total cholesterol.

On the other hand, the higher the carbohydrate intake, the lower the level of CHD risk factors and HbA(1c).

All subjects also underwent an electron beam CT scan to calculate their coronary artery calcium (CAC), a strong predictor of CHD events such as heart attacks. The study found that

“A high-fat diet and higher intake of protein were associated with greater odds of CAC, while higher carbohydrate intake was associated with reduced odds of CAC.”

The bottom line: restricting your carbohydrate intake inevitably means eating less plants and more animal foods, fats and oils. Extreme low-carb diets cause spectacular initial weight loss because they deplete your liver and muscle stores of glycogen (“animal starch”). The average adult has about 500 g of stored glycogen, and each gram of glycogen holds 3 g of water, so when glycogen is mobilised to top up a flagging blood sugar level, your scale weight will drop dramatically.

However, a carefully-conducted metabolic ward study funded by the US National Institutes of Health clearly demonstrated that restricting dietary fat resulted in greater loss of body fat than restricting carbohydrates.

So not only do low-carb diets shorten your lifespan, they don’t even work when it comes to losing body fat. That’s a bad deal all around.

Confused by contradictory weight loss claims? Need help with refining your nutrition plan to achieve and maintain your optimal weight and body composition? Apply for a Roadmap to Optimal Health Consultation today, or join EmpowerEd to watch the February 2018 Deep Dive webinar, “Optimising Weight Management on a Plant-Based Diet”.

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