1 May 2008

Your Questions Answered

We are often asked about reduced fat foods. Here, dietitian and nutritionist Catherine Saxelby explains when to opt for ‘light’ and when to be wary of the low fat claims on the packet.


I’m trying to lose a little weight, so should I be buying light foods?
Low fat or ‘light’ food products are very popular for weight loss and weight management. But not all ‘lite’ foods are the same. You really need to read the labels. They all have 25–30% less fat. But they’re not much help for weight loss UNLESS they also have fewer calories. Here’s a quick guide to help you be a savvy shopper:

  • Good choice – Low fat or light versions of milk, cream, sour cream, coconut milk, evaporated milk, Cheddar cheese, beer and margarine. For instance, swap full-fat milk for reduced fat milk and you save 6 grams of fat for each glass you drink.
  • Be wary – Light versions of chocolate, ice cream, muffins, biscuits and potato crisps have extra sugar and starches (as well as thickeners or gums) to improve the lighter product’s texture and mouth feel. For example, when I compared a light cream-filled biscuit with the regular one, I was surprised to discover it only saves you 2 calories despite the fact it's got 35% per cent less fat than the regular one!
  • Forget it – Light olive oil, light gravy and lightly-salted crisps are lighter in colour, salt or texture – not calories.
So, what’s the bottom line? Apart from the real benefits of reduced fat dairy foods, a small portion of the ‘real thing’ as an occasional treat is a smarter choice than a big serving of the light alternative.

Loved the piece on chocolate and fund raising last month. Any suggestions for healthy school lunches that won’t boomerang?

Here’s a great suggestion from one of our Canadian colleagues that may help you come up with lunches that don’t come home untouched. ‘With three school-age kids to make lunches for, the combinations of who likes what, and who can take what for lunch (although all three of my kids adore strawberries, my son has a classmate who is deathly allergic to them, so J can’t take them for lunch) is too much for my brain to keep straight (especially before my morning coffee has kicked in). So I devised a spreadsheet, stuck on the fridge, of all the various lunch options (sandwiches, other eg: baked beans, fruit, veggies, grated cheese, ‘treats’, etc.). This really streamlines things, where I can look over at the list and get an idea of what to pack! And yes, I have found that when the kids are more involved, there is generally higher acceptance of what is packed. The Waste-free Lunches website has a special section that may be helpful: Quick Reference Lunch Foods.



Anonymous said...

Would be interesting to hear how you would respond to the May 23 New York Times article on diabetes and low GI diets, in which they cite top doctors as saying:

“The notion that glycemic index matters makes intuitive sense,” said Dr. John M. Miles, a diabetes expert at the Mayo Clinic. “A lot of people have strong feelings on the subject. But the evidence just isn’t there.”

Dr. Xavier Pi-Sunyer, an endocrinologist and diabetes expert at St Luke’s-Roosevelt Hospital in New York, agreed. Given the new findings, “It seems unwise at this point to burden Type 2 diabetes patients with trying to pick and choose among different high- and low-glycemic-index foods,” he wrote in a recent review of the evidence.

Anonymous said...

I, too, would like to hear your comments on the recent Canadian study on diabetes and carbohydrates. It can be found here http://www.ajcn.org/cgi/content/abstract/87/1/114

GI Group said...

We reported on the Canadian study you mention in February 2008 GI News. But to save you the bother of hunting it up, here's what we said.

The story was headed: Lower GI diet cuts inflammation even in well-controlled diabetes.

"One hundred and sixty two adults with well-managed diabetes took part in a Canadian study reported in AJCN (January 2008) to see if a low GI diet could offer any additional benefits. The authors found that the best measure of blood glucose control (glycated hemoglobin or A1c) showed no further improvement but C-reative protein levels (CRP – a protein produced in the liver and reportedly a good predictor of the onset of cardiovascular disease) was 30% less in those on a lower GI diet compared with those on two other healthy diets. That spells less inflammation and therefore lower risk of all diseases with an inflammatory component, including heart disease and osteoarthritis.

The researchers set out to compare the effects of changing carb quality (its GI) and carb quantity in managing type 2 diabetes. At the outset of the year-long trial, all the participants already had optimal glycemic control by diet alone (HbA1C 6.0–7.0). After 12 months, the researchers report that while long-term HbA1C was not affected by either the quality or quantity of carb in the diets, two hour post-meal glucose levels and CRP were significantly reduced in those on the lower GI diet.

GI Group: This study is one of the best of its kind, but what a pity the authors recruited subjects who were so well controlled that further improvements were unlikely. If we want to nit-pick, we could say that what the authors called 'the low GI diet' is not really a low GI diet at all. Its GI of 55 is not much lower than what the average person in the developed world eats right now (i.e. the average diet has a GI of 54–58, glucose = 100). What we now know from observational/cohort studies is that the GI of the diet of the people in the lowest quintile (20% of the population) is about 40–45. Similarly, the randomised controlled trials that have shown positive affects of low GI diets on the management of existing diabetes also have an average GI of around 45. Therefore, you need to lower the average GI of the diet to these levels to see a reduction in the risk of chronic diseases like diabetes and heart disease, and to see significant improvements in their management. It’s achievable. How?

Substitute low for high GI foods in your everyday meals and snacks, especially in the breads and cereals you choose. Breakfast in particular is your opportunity to go for gold by selecting a low GI breakfast cereal. Don't assume that adding milk to crispy flakes makes it a low GI meal. If you don’t eat breakfast cereal, make sure you choose a low GI bread for your toast, and of course low GI breads are a must for those sandwiches at lunch."

GI Group said...

Re The New York Times piece:
You have quoted selectively from this. The points in the feature made by Drs Tom Wolever and David Ludwig, endocrinologists who have been researching this area for 20 to 30 years are very important. We include them here so GI News readers can see that the New York Times piece was in fact balanced.

Dr. David Ludwig, an endocrinologist at Children’s Hospital in Boston and an associate professor at Harvard Medical School said:
“High-glycemic foods like refined grains raise blood sugar levels two to three times higher than unprocessed foods with a low glycemic index. When blood sugar levels spike, the body must churn out insulin to move glucose out of the bloodstream and into cells, where it is used for energy.

“If you’re eating high-glycemic foods meal after meal, snack after snack, day after day, that’s going to put a lot of stress on the system that produces insulin,” Dr. Ludwig said. “If the system is already compromised due to a family history of diabetes, those rapid swings of blood sugar could make a difference between remaining healthy or decompensating into Type 2 diabetes.”

Dr. Ludwig cites a study he conducted in which rats fed foods high on the glycemic index lost lean muscle mass, gained body fat and began to lose their ability to control blood sugar.

“A high percentage of insulin-producing cells in the high-glycemic rats were undergoing a process of destruction, disruptions in their architecture and scarring,” Dr. Ludwig said. The same thing, he suspects, happens in people.

Dr. Thomas Wolever, a University of Toronto researcher who led the Canadian trial [mentioned in another question posted here], noted that those who ate low-glycemic-index foods showed improvements in blood sugar control after meals, which may be a more important measure of glucose control than the fasting glucose test. They also had reductions in levels of C-reactive protein, a marker for inflammation that also appears to be linked to diabetes risk.

Low-glycemic diets may have another crucial advantage, Dr. Wolever suggested: they help some people shed pounds. “I’ve had people tell me it’s the only way they’ve been able to lose weight,” he said.

“There’s no question that if we can get people to lose 5 or 10 pounds, we’ll be doing them a world of good,” Dr. Wolever said.