The FastDay Forum

There seem to be a number of postings which hint that carbohydrates are (very broadly) "bad", or at least "not as good as" protein and fat in a sensible diet, and should be restricted.

I am struggling to understand this, as I rely on complex carbohydrates (vegetables, wholegrains, fruit) as the primary component of my diet - and, touch wood, I've generally been remarkably fit and healthy all my life.

Could someone please explain the rationale behind the idea that a mainly carbohydrate-based diet isn't as "good" as a mainly protein/fat-based diet, or at least that we should "cut down on" our carbohydrate consumption, as I feel that I'm missing something here?

(Please excuse my over-simplification of the issue for the sake of clarity.)

Thank you!

[carorees]

Mostly these days a high carb diet consists of high sugar and refines white carbs, these are the trouble makers not the complex carbs you get in vegetables and whole grains. The high GI of the refined carbs drives insulin levels up and that cascades into a host of other problems. Particularly when combined with saturated fats (e.g. in cake, burgers etc). On fast days carbohydrates that release significant amounts of insulin can increase cravings and impede fat burning. From an evolutionary perspective we are not designed to eat much in the way of high GI foods...honey occasionally perhaps and fruit in season would have been the only sources of sugar. Whole grains would also have been eaten when in season. Saturated fat is uncommon "in the wild" too, so we are not set up to cope with large amounts of sugar and fat. Doesn't stop me eating cake on feed days though!

Your diet sounds very healthy!

Firstly there are no carbohydrates that you have to eat, unlike essential fats and essential amino acids (protein), so if you're going to cut down on a food group then carbohydrates are the least detrimental as you won't go short of anything essential.

Secondly there is the "insulin hypothesis" that carbohydrate intake leads to elevated blood sugar, this creates an insulin response and insulin is the primary hormone responsible for fat storage.

So the argument goes - high carbohydrate intake = high insulin levels = increased tendency to fat storage or increased difficulty reducing adipose fat stores.

In randomised clinical trials reduced carbohydrate diets fare better than alternatives in most (if not all) trials that produce a statistically significant difference between diets tested. High carbohydrate diets seldom win.

Low GI vegetables don't contain high levels of carbs and aren't a problem. Wholegrains and potato and sweet fruits are high GI carbohydrates and fruit is simple sugars and not complex carbs at all (not that "complex" helps anything).

Carbs do tend to be very people-specific - some bodies can cope with plenty of them, others find that a carb-heavy diet can make them bloated and sluggish, and they aren't as filling and satisfying as fat/ protein. So there's a wee bit of trial and error to find out what works for you.

Good complex carbs are essential in a healthy diet, and I would not advocate cutting out one food group. But they do tend to be calorie heavy as well - one slice of bread is about 100 calories, and even a small portion of pasta or rice will quickly be over 100 cals. That's fine on non-fast days, but when you've only got 500 to play with, those heavy calorie hitters take a big bite (ha-ha) out of your allowance.

Good complex carbs are essential in a healthy diet.

Except there are no carbohydrates you need to eat, "good" "complex" or otherwise. Your body evolved to work without them.

In my opinion someone wanting to lose 500 calories from their food intake would be well advised to lose 125 grams of starch, sugars, etc and not the equivalent protein or fat.

Please state what is opinion and what is demonstrable fact supported by evidence.

Thank you all for your helpful responses, much appreciated.

PhilT, may I ask for clarification (without intending to be provocative or argumentative!)?

If "there are no carbohydrates you need to eat", how would the digestive system operate correctly on a carbohydrate-free diet? Isn't it almost entirely the complex carbohydrates which come packaged with vital fibre, rather than fat or protein?

Also - are ALL the necessary vitamins/minerals contained in protein and fat? (This seems to be contrary to what I was taught, but I'm willing to be corrected if I'm wrong!)

[carorees]

Vegetables contain fibre, vitamins, minerals and varying amounts of carbohydrate from high (potatoes, carrots etc) to low (celery, cabbage). Carbs in vegetables is not the issue.

Fibre isn't vital. If you're in a coma etc they feed you liquids through tubes. Also there is a lack of consensus in general about fibre - http://www.drbriffa.com/2013/03/05/stud ... -symptoms/

You can eat something like linseed (flax) which has at least 15 times more fibre than carbohydrates, or other "pure" fibres. I'm not advocating this as an eating plan, but to illustrate the technical point about the necessity or otherwise of various nutrients.

You can get all the minerals and vitamins (fibre too) without eating more than 20g of carbohydrates per day from veg etc. Of course you can take a 100% of RDA mineral and vitamin supplement without any "food" too.

There are many nutritious vegetables that you would struggle to get much carbohydrate from such as brocolli, cauliflower, beansprouts, runner beans etc. Many people who do a low-carb diet cut out the starchy carbs and replace it with these sort of vegetables rather than eat more meat and fat.

I tend to take a low carb approach ( not a requirement of doing 5:2 ) and I now eat much more and a wider variety of vegetables than I used to. I include things like olives, avacados, nuts that I didn't used to eat much of prior to doing the low-carb.

Dr John Briffa's book Escape the diet trap is a good read, also Zoe Harcombe's The Obesity Epidemic, They both explain in a way that is easy to understand. Low Carb is the only way I can lose weight, but I prefer to say low sugar.

Dr Briffa's book is excellent. Low carb is a revelation. As an ex carboholic, I think that obesity is all about the sugar/carb thing.

Gary Taubes' Why We Get Fat was the book that convinced me to cut down refined sugar.

Never quite managed it until I started fasting though.

Just eaten a third of a packet of Pasta n Sauce (tomato) and feel bloated :0( fast day tomorrow hurrah!

I guess it must be "horses for courses" then. I would very quickly become very ill indeed if I tried to subsist mainly on fat and protein.

Thank goodness we're not all the same

It's a shame in some ways that we're not all the same. It would certainly make life easier if we all responded to the same diet uniformly. There are some carbs that I particularly like and miss but then I know how they effect me in terms of how I feel and how much I weigh.