Lower GI carbs, compared to higher GI ones, found to improve satiety and fat-burning in women

I think conventional nutritional advice (as dispensed by our Governments and health professionals) puts generally too much emphasis on carbohydrate, including forms of this that tend to cause considerable disruption in blood sugar and insulin levels. The consumption of so-called ‘high glycaemic index’ (high GI) carbohydrates have been linked with an increase in risk of all manner of ills including weight gain, type 2 diabetes, cardiovascular disease and gallbladder disease. So, as a general rule I advise individuals consuming carbohydrate to stick as much as possible to low GI ones, such as green vegetables, tomatoes and pulses.

Another advantage of lower GI foods relates to satiety. Quite a few studies have found that calorie-for-calorie, lower GI foods sate the appetite more effectively than higher GI ones. Obviously, this has important implications for those seeking to moderate the amount that they eat without going hungry. I was interested to read of a recent study which assessed the impact of glycaemic index on satiety in a group of 8 sedentary women [1]. On separate days the women were fed a high- or low-GI breakfast. Some hours later they were given a set lunch to eat. After this, the women were asked to rate how satisfied they were.

Overall, women found they felt fuller after lunch on the day that they had eaten the lower GI breakfast.

This finding raised the possibility that eating a low GI meal, compared to a higher GI one, can lead to greater satisfaction from a subsequent meal, and perhaps less food intake overall too.

This is a potentially important finding, but it was not the only focus of this research. The investigators were also concerned with the impact that the GI of food may have on the metabolism of fat in the body. The investigators point out that in previous research, the ingestion of lower GI carbs led to enhanced fat burning during exercise in physically trained men and women. The investigators were keen to see if the same held true for more sedentary individuals. Metabolism of fat was assessed while women were sedentary for 3 hours after breakfast, and then during a further hour during which they walked.

Overall, fat-burning was greater during both the sedentary spell and during exercise after the low-GI compared to the higher GI breakfast.

What this study has found, therefore, is that lower GI carbs, compared to higher GI ones, can lead to improved fat burning and satiety for several hours. These seem to me to be very good reasons for choosing low GI carbs, over higher GI ones, wherever possible.

References:

1. Fat Oxidation during Exercise and Satiety during Recovery Are Increased following a Stevenson EJ, et al. Low-Glycemic Index Breakfast in Sedentary Women. J Nutr. 2009 Mar 25 [Epub ahead of print]

4 Responses to Lower GI carbs, compared to higher GI ones, found to improve satiety and fat-burning in women

  1. CJP 30 March 2009 at 11:00 am #

    I wonder would the effect be similar between male and female?
    Was macro-nutrient composition similar between the two diets.?
    Could it be that a slower release of glucose from low GI foods facilitated more balanced insulin levels? Could then the mechanism be the one supported by Barry Sears that Glucagon and Insulin work in balance and at an optimal function to enhance release from adipose (fatty) tissue?

    I support the view that lower GI/GL can be satisfying and additionally it also seems to confer improved control of cravings. Flipping the coin, it seems plain to me there is an addictive side to high GI that can manifest itself in loss of control of appetite resultant in eating to great excess. (An opinion based only upon anecdotal personal observation.)
    Prof John Stein is a proponent of a argument that there are behavioural implications for society arising from some disruptive features of the modern westernized (high GI) diet.

    The modern way of collecting calorie-dense food for very little direct expension of effort goes against the grain of evolutionary precedent.
    However, to get that message across to our Governments, their Committees, Agencies, and some Health Service Professionals seemingly constitutes some not inconsiderable challenge. (Just an opinion)

  2. Trinkwasser 1 April 2009 at 8:46 pm #

    Depends IMO how far your pancreas has disintegrated. I find some GI values suspect – *for me* wheat is about as bad as pure sugar (familial and not uncommon) yet I can eat pizza or Dreamfields pasta in suitably small quantities without my BG spiking as I have zero Phase 1 insulin but a pretty decent Phase 2 response. Others whose Phase 2 has decreased but can still generate some Phase 1 can eat things like bananas which to me are but a distant memory. In general though I tend to keep my carbs to around 60 – 100g where I am mostly in control of my BG and lipids and running on ketones and I don’t frighten either my pancreas or my liver – I used to be prone to reactive hypoglycemia and also glucose liver dumps when the system overreacts. When I do need carbs I mostly use combinations of oatcakes and nut butter or similar, which reduces the GI to something my pancreas can deal with, but most of my carb input is from non-starch sources.

    Without the BG spikes and ensuing insulin spikes many of us find the carb cravings evaporate. Sometimes low GI is enough to do this, but if this still results in dyslipidemia it’s best to cut the carb amount as well as their speed.

    Most Type 2s find we are most carb intolerant (highest insulin resistance) at breakfast, which is the meal those annoying dieticians insist we stuff our faces with carbs and starch sandwiches washed down with orange juice. This Does Not Work! Would be interesting to see what effect differing GI meals have in the evening.

  3. Chris 2 April 2009 at 4:58 pm #

    “However, to get that message across to our Governments, their Committees, Agencies, and some Health Service Professionals seemingly constitutes some not inconsiderable challenge. (Just an opinion)”

    http://www.fsascience.net/2009/04/01/from_science_to_policy

    Let’s live in hope.

    http://www.newscientist.com/article/mg20127015.900-realities-of-boozing-are-tough-to-swallow.html

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