Cutting Carbs: What does the latest evidence tell us?

Cutting Carbs: What does the latest evidence tell us?

Carbohydrates. Poor old carbs. They have copped so much hate from so many different directions. But is this hate warranted?

According to the most reliable source of nutritional advice, ‘the internet’ (2019), carbs make you fat, bloated and give you diabetes. The latest popular diet trend; the keto diet, requests that you kindly cut down on your carbs, you greedy bread-loving monster. 

Is there any truth to this? Should you cut down on carbs?

Studies have shown that you can successfully lose weight on a low carb diet. However, when compared to other diets, overall, the weight lost on a low carb diet is virtually the same as every other diet. 

The important point here is that when people put themselves on a diet, they tend to be more conscious of what they’re eating, and tend to eat better. They eat less processed food, more fresh food, and are less likely to overeat. 

A calorie deficit is what is responsible for the weight loss, there is not something special about removing carbs from the diet. In fact, studies show that when someone significantly reduces carbs, they lose a great deal of water from the body, giving the illusion of fat loss. This ‘weight’ loss is not sustained in the long term. 

If you’re thinking about writing a book, why not write one on the keto diet? I daresay you’ll sell a few copies.

For unexplainable reasons, the keto diet seems to be replacing the paleo diet as the most attractive diet of the moment. The paleo diet involves avoiding sugar and grains, which may or may not lead to a reduced carbohydrate intake, depending on what these foods are replaced with. The keto diet specifically recommends a particularly low carbohydrate intake, encouraging fat as the primary fuel instead of carbohydrates. 

The keto diet has been shown to have some real health benefits. For people with severe, untreatable epilepsy. That’s correct, due to some very specific biological reasons, this diet reduces seizures in epileptics that do not respond to medicine.

Is the keto diet suitable for a non-epileptic individual? 

Carbohydrates are the main source of fuel for humans. They keep the processes inside our body running smoothly. They give our cells the energy needed to function and repair body tissue. They make us feel sane instead of hangry.

Most countries have some sort of ideal food pyramid, guide or plate that tells its citizens what they should be aiming for in their diet. Across the globe, a common theme is that carbohydrates should be providing ~50% of an individual’s total energy consumption. This recommendation is based on hundreds of thousands of high-quality scientific studies.

Not all carbs are equal, however. Just like fats – there are ‘good’ and ‘bad’ carbs. Refined carbs such as white bread, white pasta and sugar are examples of carbs you should aim to minimise. These foods have been stripped of their fibre and various other nutrients. 

Our ‘good’ carbs haven’t gone through this refining process, and include wholegrain bread and wholemeal pasta, legumes (e.g. baked beans, chickpeas and lentils), vegetables and fruit.

My concern in following a low carb diet is that this may encourage you to reduce these good, wholesome foods – all in the favour of potentially increasing meat and other sources of not-so-healthy fats that lack important nutrients, chiefly fibre. And for what reason?

Do you love eating bread?

Do you love pasta? Do you dream of pizza, risotto, noodles and pancakes?

If you said no to any of the above, I don’t think our relationship is going to last the length of this article.

A recent systematic review and meta-analyses published this year in the Lancet (a highly regarded medical journal) found that fibre intake was associated with a “15–30% decrease in all-cause and cardiovascular related mortality, and incidence of coronary heart disease, stroke incidence and mortality, type 2 diabetes, and colorectal cancer”. 

The study advised that the greatest health benefits would be obtained by aiming for 25-29g of fibre per day.

As a guide, here’s an example of how you might get in this amount of fibre:

Breakfast: 2 slices of 100% wholemeal bread = 4.5g + half an avocado = 4g

Lunch: 1 cup of cooked brown rice = 3.5g + 1 cup of cooked vegetables = 5g

Dinner: 1 bowl of cooked wholemeal pasta = 3g + half a cup of chickpeas = 6g + 1 cup of salad = 2g

Total fibre = 28g

Higher intakes of dietary fibre could confer even greater benefit to protect against cardiovascular diseases, type 2 diabetes, and colorectal and breast cancer. Similar findings for whole grain intake were observed.

I find this striking. How can we honestly sit around dissing bread and feeling guilty about that enormous bowl of pasta we ate, when the most compelling evidence tells us the opposite is true? I google “healthy meal ideas” (yes, even nutritionists lack inspiration sometimes) and I see an overwhelming absence of wholegrain carbs. Salmon and steamed vegetables? Beef and salad with a red wine vinaigrette? Perhaps a tofu and vegetable stir fry? An egg cooked inside the hollow of an avocado, just to avoid putting it on a piece of toast? No thank you - particularly to that last one.

The list goes on! I can see why it might be easy to see carbs as the source of all evil.

But really, there is no reason you shouldn’t have your bread and pasta. Do your best to find wholegrain sources of these foods and enjoy them. Relish in the feeling of satisfaction and happiness that only carbs can provide. I love you, carbs.

Lucy x

References

Reynolds, A., Mann, J., Cummings, J., Winter, N., Mete, E., & Te Morenga, L. (2019). Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. The Lancet.

Clarke, C., & Best, T. (2017). Low-carbohydrate, high-fat dieters: Characteristic food choice motivations, health perceptions and behaviours. Food Quality and Preference62, 162-171.

Brinkworth, G. D., Luscombe‐Marsh, N. D., Thompson, C. H., Noakes, M., Buckley, J. D., Wittert, G., & Wilson, C. J. (2016). Long‐term effects of very low‐carbohydrate and high‐carbohydrate weight‐loss diets on psychological health in obese adults with type 2 diabetes: randomized controlled trial. Journal of internal medicine280(4), 388-397.

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