Tuesday, October 26, 2010

Low joule sweeteners & appetite

Sweetening agents in food or as a powder or tablet have been around for many years. I have already told you that my folks used saccharin during the sugar restrictions of the 2nd World War. Much misinformation on sweeteners circulates the internet because the world loves to hate stuff they don’t understand.

One thought has been that sweeteners like aspartame (Nutrasweet) at best didn’t make you eat less kilojoules and at worst, made you overeat, countering the close-to-zero calories they offer.

Sugar vs sweeteners

Sugar has been thought as a culprit in weight gain since the 1960s, so replacing sugar with a sweet substitute that provided very few calories was always seen as part of the remedy and would help weight loss. To test whether people compensated for the “missing kilojoules” when consuming low joule sweeteners, researchers first gave test subjects a “pre-load” meal that had either sucrose (cane sugar), or the low joule sweeteners aspartame or stevia (a sweet extract from the leaf of Stevia rebaudiana). They were blind as to which pre-load snack they got.

The participants had a controlled breakfast. Later in the day they were given one of the three pre-load snacks, followed 20 minutes later by a regular lunch. In the evening they were given another of the three pre-loads (with either sucrose, aspartame or stevia) followed by a dinner to their liking.

Appetite not affected

The pre-load snack had an extra 200 Cals (835 kJ) when the sugar was added, compared to the sweetener. If the low joule sweeteners aspartame or stevia had no effect on appetite, then the subjects should have made up the difference in kilojoules by the end of the day, such that they ate the same number of kilojoules independent of whether the pre-load meal had sugar or sweetener.

At the end of the day, when the pre-load snack had a low joule sweetener, the people ate around 300 Cals (1255 kJ) less food than those who had sugar included. Conclusion: low joule sweeteners helped lower the amount of Cals/kJs eaten over 24 hours.


The pre-load snacks were solid (crackers and cream cheese sweetened with sugar, stevia or aspartame). The results may have been different if the choice was regular or diet soft drink. The people chosen did not have psychological problems with their food. Had they been aware of the kilojoule content of their snacks (or knew they were drinking diet soft drink) they may have made psychological adjustments to what they chose at lunch or dinner. The study was over 24 hours and a compensatory calorie catch-up may have occurred on subsequent days. All the same, this research is consistent with other research suggesting that “diet” food and drinks can help weight control in many people.

What does it all mean?

When I fly I usually have a water, Diet Coke or Pepsi Max (I’m one of those who can’t really tell the difference) to counter the dry atmosphere in an aircraft. The occasional diet soft drink or food with a low kilojoule sweetener can play its part in stopping overeating. As always, controlling your weight is about eating well and being fit. Low joule sweetened foods can help in a small way.

Reference: Appetite 2010; 55: 37-43

Hash brown content of Harley Davidson's

While reading Martin Lindstrom’s book Buyology (http://www.martinlindstrom.com) he mentioned that Harley Davidson had tried to trade mark its engine sound when Japanese bike manufacturers tried to mimic that engine rumble. He described it as the signature fast “potato-potato-potato” sound. I hadn’t heard the sound described that way before. You probably have, and so have many others (put Harley and potato into your search engine).

Ok, nothing to do with food. I just liked the analogy, but not around my house after 10pm please (because the sound wedges into my consciousness and fries my sleep. Hey, I know it’s not funny, but I didn’t think you would read this far). The photo was taken at the Elvis Festival, Parkes, NSW in January 2008. From memory, Kelvin the owner, paid $35,000 for it. And yes, he has the complete Elvis outfit and wig.

Monday, October 11, 2010

Popeye didn't eat spinach for iron

Three generations of children have been told to eat their spinach so they get enough iron and grow up to be a strong as Popeye. Leaving aside the fact that muscle strength has got more to do with training and eating well, more than a focus on a single nutrient, we face those funny things called facts.

Spinach and iron

Spinach does contain iron. Half a cup of cooked spinach provides around 4 mg of iron. That’s pretty impressive considering the average bloke needs 8 mg a day and young ladies need 18 mg a day. Most other vegetables barely give you 1 mg of iron per half cup served. So, spinach has quite a bit of iron. And that’s about as far as some people look.

Although spinach is high in iron it is a lousy source of iron. How’s that? Well, it all revolves around the word “bio-availability”, that is, the ability of the body to absorb a nutrient from the intestines and use it within the body. Most of the iron in spinach is bound to oxalate (in the form of ferrous oxalate) and you do not have a digestive enzyme to split that binding to release the iron. That means that most, estimated at 95%, of the iron goes in one end and out the other about a day later. Spinach is iron’s way of taking a 10 metre (11 yd) voyage through your guts.

The decimal point fallacy

Now, Popeye is unlikely to have known that because he was created around 1929, featuring in his own cartoon in December 1930. A British Medical Journal paper from 1981 claimed that the fallacy of spinach being high in iron came about because the decimal point was placed in the wrong spot in the original analysis back in the 19th century, giving spinach an iron content ten times more than it was in reality.

Earlier this year, Dr Mike Sutton from Nottingham Trent University in the UK, refutes the whole argument stating that there is no evidence that a decimal point was ever placed in the wrong spot. He has even written to author of the BMJ article and says the response from the author provided no proof for the claim.

The really, really interesting bit

Well, to me at least. OK, so spinach is not a great source of iron and it never appeared to be. When Popeye was created in 1930 we knew about the minerals like iron and calcium and only the vitamins A, B1, C, D and E. Vitamins like folate, B12 and niacin were yet to be isolated.

Did Popeye himself say he ate spinach for iron? No. Not once, according to Mike Sutton. He did, on 3rd July 1932, mention that he ate spinach for one particular nutrient. Vitamin A (see cartoon). You and I know that there isn’t pure vitamin A in spinach; it’s in the pre-vitamin A form of beta-carotene. All the same, Popeye ate spinach for a vitamin, not a mineral.

What does it all mean?

It is wonderful when someone goes that extra distance to get information. So, hat’s off to Mike Sutton. I didn’t take Mike’s word for it. I went and bought the first two years of Popeye cartoons (because I yam what I yam), and I agree with Mike: Popeye only mentions vitamin A. Popeye is right, spinach is a great source of beta-carotene (and folate). Eat your spinach for the vitamins, not for the minerals.

If you would like to read the complete report by Mike Sutton then just got to: http://www5.in.tum.de/~huckle/Sutton_Spinach_Iron_and_Popeye_March_2010.pdf. Warning: it is a 35 page in-depth study as you might expect from a criminologist, which is just what Mike is.

Reference: British Medical Journal 1981; 283: 1671-1674