Don’t Believe The Net Carbs Fallacy

Net Carbs LabelIf you are on a low-carb diet and have been tempted by those brand name snack bars that state they are suitable for consumption on all phases of a low-carb diet, hold your resolve and think again, because it’s very likely they will either impede or stall your weight loss, or even cause the pounds to start creeping back on. And that goes for any low-carb alternative sweet tasting snacks and drinks, whether they contain a sugar alcohol (polyol: polyhydric alcohol) such as maltitol or xylitol, sweeteners such as aspartame or saccharine, and so on.

Some low-carb professionals, including good old Dr Atkins, have stated that non-sugar sweeteners can be safe for low carb dieters. In the 2002 edition of his New Diet Revolution book, he says that, “When doing Atkins” you should not count “non-blood sugar impacting carbs, including polydextrose, glycerine, and sugar alcohol, as well as fibre”.

However, in this article I explain why sweeteners and sugar alcohols are unhelpful and even counter-productive for low-carb dieters. But before moving on, feast your eyes (but not your stomach) on this list of ingredients found in a selection of the best-selling low-carb snack bars:

  • Acesulfame Potassium
  • Almonds
  • Calcium Carbonate
  • Cellulose
  • Chocolate Liquor (Processed with Alkali)
  • Cocoa Butter
  • Cocoa Powder (Processed with Alkali)
  • Coconut
  • Dicalcium Phosphate
  • Glycerin
  • Hydrolyzed Gelatin
  • maltitol
  • Natural and Artificial Flavors
  • Oat Fiber
  • Oat Flour
  • Palm Kernel And Palm Oil
  • Polydextrose
  • Soy Lecithin
  • Soy Protein Isolate
  • Soybeans
  • Sucralose
  • Sunflower Oil
  • Vanilla Extract
  • Whey Protein Isolate
  • Whole Grain Rolled Oats
  • Whole Milk Powder

Although many of these items, such as almonds, cocoa butter, coconut and so forth, are fine, if you are trying to eat natural, wholesome, low-carb foods, do you really want to be putting many of those other things into your body (and what about the warnings on these packs that often say “Contains wheat”)?

If it tastes sweet then you’re going to regret it

SweetsHuman beings evolved through millions of years to develop a highly sophisticated and fine-tuned body, with a remarkably efficient and powerful means of obtaining and using energy: namely processing what we eat and drink. As part of this evolution, our taste buds developed to the point that just a few molecules of many substances can trigger them, so that things likely to be poisonous would instantly taste disgusting and we would spit them out.

At the same time we developed the well-known taste sensations of sweet, sour, salty, and bitter. More recently the Japanese term umami has been added to this list to indicate our ability to taste savoury items, and I would further add that we have the ability to taste fat too. Just take a teaspoon of double (or heavy) cream and let it flow over your tongue to feel the sensation and taste of it. Then try a few other fatty foods like cheese or olive oil and I’m sure you’ll soon agree.

Anyway, this meant that when we needed salt we would crave and seek it out, and by combining the types of taste sensations together we could recognise all manner of foods and seek them out when our bodies told us we needed them. And one of the most powerful signals turned out to be sweetness. You see, it’s possible to fix almost any imperfection in a food by adding sugar to it, because sweetness overrides all the other taste sensations – it’s that important.

But why? Well, because sweet things almost always contain fructose and glucose, which are extremely powerful energy sources, but ones that used to be highly scarce in nature. Yes there was honey if you were prepared to fight the bees for it, and then there were fruits in the autumn. As it happens, by some amazing coincidence (or more likely evolutionary adaptation), high-energy fruits ripen and become sweet not long before the winter begins to set in.

So what did our cave dwelling ancestors do, then? Well, they were hunters and gatherers and didn’t do any farming to speak of, so when the fruit ripened they would eat it – as much as they could. And this would make them put on weight due to the sugars being stored as fat. Which was exactly what their bodies were designed to do, because the winter was coming and they were going to need that fat to subside through a scarcity of food until the spring returned.

So, by making these foods taste enticingly sweet, our bodies ensured we would use them to build up our fat reserves. But the trouble is that we no-longer have a long winters of limited food rations. Even the poorest of us in the western world can find something to eat, somehow. And generally the cheapest foods are the ones packed with carbohydrates, and enhanced with sugar to make them taste good (and sell well).

The evolutionary development of the sweetness sensation that served us so well for millions of years is now a danger to us, because we have access to nearly all the foods we could want, nearly all the time. And our bodies continue to tell us to eat sweet things whenever we can find them – that’s what they’ve evolved to do.

OK, I’ll give you that sugar is bad, but sweeteners?

SweetenersWhat happens when you take a bite of any food, is that enzymes in your saliva start breaking it down, your taste buds react to what they find and signals are sent to your brain informing it about what it has detected you are about to swallow. This advance warning mechanism then sends signals to the stomach to produce acid, and the liver to produce bile if fat is being eaten, and the pancreas to produce insulin if the food is sweet.

If you have, indeed, eaten something sugary, the insulin will then work to lower the glucose levels that start entering your blood back to a safe level, by the process of converting the glucose into fat and then storing it into your fat cells. But what if you haven’t eaten any sugar, or even any carbohydrates for that matter (since carbs comprise pairs of glucose molecules attached to each other)?

Well, the insulin has to be used up and any and all available carbs found in your body will be processed into fat, not just excess ones above your energy requirements. At the same time your body becomes desperate for some carbohydrates for the insulin to be used up on, and you become ravenously hungry. This is why ‘diet’ soda drinks actually lead to greater hunger and have been shown to also lead to greater increase in weight than full sugar (or high fructose corn syrup) sodas.

Net carbs are not net carbs

Assorted carbohydratesSo, now you know why things that taste like sugar but aren’t can have the same (or worse) effect on your body than things that are sugar. And that really summarises the whole problem with artificial sweeteners, and is all you really need to know if you are having trouble on a low-carb diet due to sweeteners. Just don’t use them. But the story is bigger than that because it’s not just sugars that the body turns into fat. As I just mentioned, it can perform this trick with virtually all carbohydrates (except fibre).

However, some food producers tell us that there is such a thing as Net Carbs, wherein they deduct all carbohydrates that they say the body cannot process, and simply report those that remain. Clearly, I have no beef with discounting fibre from the carb count of a food, and most countries show the fibre percentage as a sub-section of the carbohydrates on the food packet. In fact, as Dr Robert Lustig explains, wherever there is sugar in nature, it is almost always packed with fibre, which mitigates its negative impact. He calls fibre “half the solution” to the obesity pandemic.

But I most certainly have a problem with companies claiming that they can discount 100% of all polyols (sugar alcohols) from the carb count of a product. A polyol is a carbohydrate that chemically is similar to both alcohol and sugar, but they don’t get you drunk and have a lower calorific value than sugar. But that’s the point, they have fewer calories – not none

Polyols vs Sugar

Maltitol syrupSugar has 4.0 calories per gram of weight. The list below details the calorific values for the main polyols for you to compare with sugar, as detailed here. These sweeteners clearly have up to ¾ the calories of normal sugar, so how can anyone claim they can be excluded from the carb count of a product?

Well, maybe you could get away with Erythritol, which has very few calories and which, if less than 1%, can usually be called 0 calories in the USA. But it still tastes sweet – don’t forget that – and you now know what the problem with sweet tasting food is.

  • 4.0 Sugar
  • 3.0 Maltitol syrup (intermediate)
  • 3.0 Maltitol syrup (regular)
  • 3.0 Maltitol syrup (high)
  • 3.0 Maltitol syrup (high-polymer)
  • 3.0 Xylitol
  • 2.8 Polyglycitol (hydrogenated starch hydrolysate)
  • 2.7 Maltitol
  • 2.5 Sorbitol
  • 2.1 Isomalt
  • 2.0 Lactitol
  • 1.5 Mannitol
  • 0.2 Erythritol

These sweeteners clearly have up to ¾ the calories of normal sugar, so how can anyone claim they can be excluded from the carb count of a product? Well, maybe you could get away with Erythritol, which has very few calories and which, if less than 1%, can usually be called 0 calories in the USA. But it still tastes sweet – don’t forget that – and you now know what the problem with sweet tasting food is.

Polyols are listed separately as a sub-section of carbohydrates on food packaging labels in most countries, and this helps to lead people to think the same way as these companies, so that low carbers may be tempted to do the maths and subtract polyols from the carb total. Actually the information about polyols is useful on these product labels, but not so that you can discount them. Oh no. You need to know when they are present, because if you consume above 10-20 grams of a polyol such as maltitol, don’t make any plans to go out anywhere before tomorrow, or you may well find yourself caught short for a toilet break (or many), due to the intense laxative effect of these substances.

Also, proponents of polyols will often argue that their glycemic index (GI) is much lower than sugar, and because it causes your blood sugar and insulin to spike less it causes less fat creation. That may be so, but while sugar has a GI of 100, maltitol has a GI of between 36 and 53 depending on type and polyglycitol has a GI of 39. So, at the very least, these sweeteners are at least 40% as bad for you as sugar. And while the other polyols have a GI of 13 or less (and a couple have 0), they still taste sweet (and you know why… etc).

My own experience

A typical pharmacyAbout 30 pounds into my own low-carb weight loss plan I was perusing a local pharmacy and encountered the dietary section, where there were a range of snack bars from different well-known diet organizations, and my attention was drawn to the low-carb offerings by the market brand leader. I was pleasantly surprised to see that these bars were applicable to all phases of their diet plan, and generally had only one or two “Net Carbs” per bar.

Although I wasn’t hungry I was curious, and was sure it couldn’t hurt, so I bought a couple and munched one on the way home. OK, it wasn’t as nice as a regular snack bar, but it seemed passable. Then in the evening I decided to eat the other bar. A couple of days later I was in another store and saw some more of them, so I thought I might as well buy a box of 5 bars and get a discount (you know where this is heading, right?).

Sure enough they were all gone in a couple of days, and then in a health food store I saw some sugar free chocolates. Some were sweetened with maltitol and some with stevia – so I bought both types, naturally. As it turns out the stevia ones left a slight after taste and I wasn’t too impressed, but the maltitol hazelnut bar tasted great, so I ate all 112 grams. Big mistake. Because starting a couple of hours later I then spent the following few hours back and forth to the bathroom.

Wow, that stuff is powerful. I even moved a spare bar I had to the medicine cabinet, having decided that was a better place for it than the larder. So I paused my attempts at snack eating for a couple of days until I stumbled across chocolates for diabetics and, upon reading the ingredients, realized they were exactly the same things, just much cheaper than buying branded low-carb products. Oh dear. The lower price convinced the part of me that always looks for bargains to buy half a dozen of these bars.

But hard as I tried to eat only one or two pieces, I would end up scoffing down a whole bar. Cravings had returned, and without any sugar in sight. So I stopped eating the chocolate bars altogether and went back to the branded low-carb bars only, but I still found that I was craving them most of the day.

So, three weeks from my first dabbling with low-carb sweet snacks, and having stalled my weight loss to practically zero, I conducted a lot more research into low-carb diets and sweeteners, and as a result of what I learned (which is passed on here) I cut them out entirely. My weight loss then kicked right back into gear and all cravings vanished.

I had learned that as a low carber I also had to educate myself to not eat anything sweet, whether sweetened with sugar, or artificially. There is one exception, though. Because I can’t do without it in this one instance, I also learned to reduce the sweetener I use in my coffee (stevia), to the minimum amount that makes the drink not taste bitter, but also not taste sweet either, so that I don’t trigger the insulin response when I drink it. Maybe one day I’ll learn to like bitter, who knows.

If it seems too good to be true…

Of course you can trust him!… it probably is. I know that. You know that. But many of us fall for the marketing blurb on diet products and convince ourselves that they wouldn’t say it worked if it didn’t. Well, there’s different types of “worked”, which all depends on the laboratory conditions, types of studies made, parameters used, methods of evaluation and so forth. If you know anything about statistics, then you know how easy it is to make any case given a large enough quantity of data. And that’s what marketers do all day long.

It’s sweet stuff that got up to ⅔ of the western world to become overweight (and half of them obese), and those of us affected know in our heart of hearts that sweet stuff is therefore unlikely to be part of the solution. As I should have told myself before biting into that first low-carb snack bar, “This seems too good…” . . . Well, you know the rest.

Long story short: If you are already using any of these products and are still achieving the weight loss you desire, then you can probably ignore most of the advice in this article as you are lucky enough not to be overly sensitive. But do bear these things in mind if you do encounter a stall in the future. If you aren’t already using them, though, my advice is simply not to start.

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  • Patricia Samlock Pattison

    does the stevia,cause the same reaction on holding on or turning into fat,as the other sweetners? An stalling weight loss?would really like to know cause it is the only sweetner I use.Don’t want to hurt my progress ! Let m
    e know,please.

  • http://robinnixon.com/ Robin Nixon

    Hi Patricia,

    If you use stevia to make something taste sweet then it might be interfering by triggering the insulin response. However, if your weight loss is working OK, don’t worry. I think I will write a short addenda about that to the article.

  • Glen

    Hi Robin,

    I have the extra-whammy of being a Type II diabetic (with the additional problem of producing very little insulin any more, like a Type I) as well as once being clinically ‘morbidly obese’.

    What helped me learn about the “net carb” fallacy was my own glycemic testing. As a diabetic who regularly tests his blood glucose levels for best overall glycemic control, I tested many of these ‘low-net-carb’ products to see how my blood glucose responded.

    I *VERY* quickly learned that low-net-carb claims seldom correspond to reduced spikes in blood glucose levels.

    I tested everything from Julian Bakery products to Quest low-net-carb bars.

    My own results show (and we’re all different): The ONLY sugar alcohol that doesn’t affect my blood glucose is pure erythritol; Maltitol/Sorbitol affect me roughly 50% as much as pure table sugar; Fiber claims are often misleading.

    I recommend anyone obese that’s trying to lose weight purchase a blood-glucose meter and some strips. Wal-Mart and other places have cheap ones, and it helps ANYONE see what effect certain foods are really having on the glucose/insulin roller-coaster…

    I also don’t recommend artificial sweeteners much as it helps keep one a slave to their “sweet tooth”. When I cut sugar and reduced sweeteners, my tastes changed to the point I found MOST products that were sweetened with anything too sweet to bear or stomach. Even things I used to previously enjoy. If I used artificial sweeteners more, and kept my “sweet tooth”, I might still be tempted by some of these…

  • Glen

    Just an FYI – I’ve read all the research I can find on the subject and there just doesn’t seem to be any evidence that artificial sweeteners truly elicit an insulin response. It’s been theorized many times, but I’ve yet seen it proven in any proper clinical trials.

    That being said, however they sure don’t help people whose tastes need to evolve (or revert back to normal) to reduce their “sweet tooth” (ie: refined carb) cravings, and I *think* they may somehow interfere with satiety signals (my own theory) ,,, but I have no way to prove either.

  • http://robinnixon.com/ Robin Nixon

    Here are just a few studies, Glen:

    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2670679/
    http://circ.ahajournals.org/content/117/6/754.abstract
    http://www.ncbi.nlm.nih.gov/pubmed/18556090
    http://www.medicalnewstoday.com/articles/261179.php
    http://care.diabetesjournals.org/content/36/9/2530
    http://www.ncbi.nlm.nih.gov/pubmed/2887500

    The wealth of evidence supporting the dangers of artificial sweeteners is growing fast. And there are even studies that show that diet soda drinkers put on more (or lose less) weight than regular soda drinkers:

    http://articles.mercola.com/sites/articles/archive/2013/07/24/diet-soda-dangers.aspx

  • http://robinnixon.com/ Robin Nixon

    Yes, erythritol has almost zero carbs, zero calories, and zero glycemic index. In theory it sounds great (as does Stevia). However, the evidence suggests that because it is sweet it may elicit an insulin response in some (or many) people.

  • Glen

    While I agree that diet sodas simply aren’t healthy, and that the jury is still out on artificial sweeteners, the evidence does NOT suggest it promotes insulin response, and never really has. That’s all I’m saying…

    The first study you linked clearly states that the artificial sweetener did NOT promote insulin response.

    The second study made no conclusions on insulin-release from artificial sweeteners. It was also epidemiological and based on food-frequency questionnaires.

    The third study is on Cephalic phase insulin release … which is also stimulated by BUTTER or even time-of-day.

    I’ve read the study in the 4th article – and I do find it compelling, however it has yet to be reproduced. There are over 100 double-blind studies with larger samples that obtained different results with regards to insulin response and NNS, so I have to remain skeptical and look forward to seeing if it *can* be reproduced.

    The fifth link is the same article in diabetes-care mentioned in the 4th link, so I already commented.

    The last study is on rats (neither of us are rats, yay) and was giving MASSIVE doses – 150g/kg bodyweight of Ace-K injected as well as steady infusion of 20 mg/kg bodyweight per minute. Do the math on the amount of Ace-K given over the course of an hour – the dosage is literally thousands of times what most people have in their products containing NNS. Much like the original saccharin studies, this one is rather ridiculous.

    I almost sound like a NNS-apologist – believe me, I’m far from it. I believe we all should eat natural/real food wherever and whenever possible, doing our utmost to avoid processed and lab-created food. However as much as I personally avoid artificial sweeteners – there is no conclusive evidence to suggest they elicit an insulin response at this point in time.

    Are they natural? Nope. Even stevia is refined. Should we avoid them? Absolutely. Do they create an insulin response though? The evidence simply doesn’t support that theory.

    So I agree with your overall idea of their safety and usage, just not the insulin-response claim.

    Thanks for allowing comments!

  • http://robinnixon.com/ Robin Nixon

    I will bow to the weight of your argument until I have learned more chemistry than I already know. I am on a continuous path of exploration in this area and will certainly be examining any and all studies I encounter on sweeteners very carefully.