The glycemic index is a measure of a carb’s effect on blood sugar. So-called “good” carbs – from bran cereal to many fruits and veggies – are lower on the glycemic index, and are central to this dietary approach to lose weight, and improve blood-sugar control and heart health. Good carbs are digested slowly, so you feel fuller longer, and your blood sugar and metabolism don’t go out of whack. By contrast, “bad” carbs, such as white bread and instant mashed potatoes, are quickly digested and released into the bloodstream, spiking blood sugar and making you hungry sooner.
You can refer many popular books to get more information about Glycemic Index of various food items and recipes based on this diet.
- You shape your diet
- You won’t be hungry
- No guidance on foods other than carbs
- Got to do homework
Glycemic-Index Diet is Ranked:
How does Glycemic-Index Diet work?
It looks simple – all you need to know is where different carbs fall on the 0 to 100 glycemic index.
- You fill up on low-GI carbs (55 and under)
- Eat smaller amounts of medium-GI carbs (56 to 69)
- And mostly nibble on high-GI carbs (70 and up)
Lists of carbs in each category are available online, or you can mine a database from the University of Sydney, which operates a GI-testing laboratory. Besides referring to these lists as needed, there’s no fussy weighing or measuring. But you’ll have to devise your menus yourself. The GI only ranks foods containing carbs, so meat, fish, and poultry, for instance, don’t have GI numbers. You’re on your own in deciding how much your diet should include. At breakfast, go for cereals made with oats, barley, or bran; at lunch, eat your sandwich on whole-grain bread; and at dinner, toss up a salad instead of baking a potato.
How much does Glycemic-Index Diet cost?
It’s hard to say. Whole-grain products, fruits, and vegetables – which should be filling your cart if you’re doing it right – are generally more expensive than highly processed foods like white bread, sugary cereals, and sweets.
Will Glycemic-Index Diet help you lose weight?
GI diets demonstrate short-term weight loss but not much more than other diets show. And the claim that eating low-GI carbs is the key to weight loss is still controversial. An advisory committee to the federal government’s 2010 Dietary Guidelines even concluded that evidence overwhelmingly shows that diets based on the glycemic index do no better at weight loss than those that aren’t, nor are they better at keeping off pounds already lost. The advisory committee to the 2015 Guidelines briefly mentioned a low-glycemic-load diet as one among many associated with weight loss – if calorie restriction is also included.
Other research is somewhat more positive. Most notably, a 2012 study published in the Journal of the American Medical Association found low-glycemic-index diets to be best at maintaining weight loss when compared to very low-carb diets (which boosted metabolism most but increased the risk of disease) and low-fat diets (which slowed metabolism most). The findings support the GI diet’s claim that “a calorie is not a calorie.” Another study published in 2014 in The American Journal of Clinical Nutrition supports low-GI and calorie-restricted diets as more effective than high-GI and low-fat diets for losing weight.
A 2011 review of 23 clinical trials of low-GI diets also showed some promise: Four studies found GI diets to be superior to others for weight loss and 10 found non statistically significant improvements in weight loss with the low-GI diets. Ultimately, however, the researchers concluded that the GI diets are no more or less effective than others in inducing weight loss. In worse news for GI dieters, another 2013 review of 20 studies found that low-carb diets and Mediterranean diets were better for weight loss than low-GI diets.
Past research on the diet is also mixed. In 2009, the independent, nonprofit Cochrane Collaboration reviewed six small, randomized controlled trials of low-GI diets tested over periods from several months to a year. Overall, low-GI dieters fared a little better than comparison dieters, losing an average of about 2 more pounds.
Here’s a closer look at a few of the trials Cochrane analyzed:
- In a 2006 study published in the Archives of Internal Medicine, 129 overweight or obese adults were assigned to one of four diets: high-carb/high-GI, high-carb/low-GI, high-protein/high-GI and high-protein/low-GI. All diets provided 1,400 to 1,900 calories a day, with reduced fat and moderate fiber. At 12 weeks, the low-GI groups had lost an average of 10 and 11 pounds while high-GI groups had lost 8 and 12 pounds. The differences in weight loss among the groups weren’t considered meaningful.
- A study of 45 overweight women, published in the American Journal of Clinical Nutrition in 2004, assigned to either a low- or high-GI diet found a slight weight-loss edge for low-GI dieters after 10 weeks, but the findings weren’t considered trustworthy.
- An even smaller study, published in 2005 also in the American Journal of Clinical Nutrition, tracked 23 obese young adults for one year, one group on a low-GI diet and the others on a low-fat diet. The low-GI dieters lost 8% of their initial body weight compared with 6% for the low-fat group, but the difference wasn’t statistically meaningful. (Still, even losing 5% of your current weight can help stave off some diseases.)
Here’s a look at some studies Cochrane didn’t review:
- A study published in the New England Journal of Medicine in 2010 examined weight-loss maintenance of 773 overweight adults on high- and low-GI diets. After 26 weeks, the low-GI dieters had regained 2 pounds less on average than their high-GI counterparts had.
- Another study, published in 2010 in Nutrition, Metabolism and Cardiovascular Diseases, compared low-GI and low-fat regimens in 202 overweight and obese adults, about half of whom had metabolic syndrome, which increases the risk of heart disease and is considered an early sign of Type 2 diabetes. After three months, the low-GI group had lost an average of 10 1/2 pounds, and the low-fat group lost 8. After a year, however, both groups had lost about 9 pounds.
- A study published in 2007 in the American Journal of Clinical Nutrition assigned 203 normal to overweight Brazilian women to either a low- or high-GI diet. After 18 months, low-GI dieters had lost an average of 1 pound compared with half a pound for the high-GI dieters.
- Three additional small trials that pitted low-GI diets against either high-GI or control diets also found no notable differences in weight loss after periods of up to a year.
How easy is Glycemic-Index Diet to follow?
The Glycemic-Index Diet is ranked #23 in the Easiest Diets to Follow
It’s moderately difficult to stick to a Glycemic-Index Diet.
Following the University of Sydney’s suggestions, a low-GI approach can be as simple as swapping the baked potato that usually accompanies your steak for a medley of zucchini, yellow squash and baby carrots.
But you won’t find a GI ranking for every food – researchers will never be able to test them all and a low-GI ranking isn’t all that determines the effect of a particular food item on your body. How the food is prepared and how ripe it is (if it’s a fruit or veggie) are just two of many wild cards. Good luck coming up with a close estimate of the effect your entire dinner (or a particular recipe for cornbread) has on your blood-sugar levels. Moreover, perfectly healthy foods might be high-GI and unhealthy ones low-GI. It adds up to a lot of confusion.
The index also isn’t helpful with noncarb foods. Without guidance, many dieters, especially those aiming to lose weight, would have a tough time designing a plan that reduces calories enough to deliver weight loss.
You can avoid some of this uncertainty with one of the many diet programs or books on the market that provide shopping lists and meal plans. Or just take the University of Sydney’s advice.
- It’s convenient but self-reliant. There aren’t many rules – cook if you want, or just dine out. But without the structure of an actual program, you’ll have to figure out how much, what, and when to eat on your own.
- There are many resources for recipes. The internet is rife with low-GI recipes. For extra inspiration, one of the many low-GI cookbooks on the market might help.
- Eating out is doable. This shouldn’t be a problem on a Glycemic-Index Diet once you have a handle on what’s low and high in the GI world.
- Timesavers aren’t available. You’re stuck with all the work if you choose to follow a general GI approach. Some books or guides might make the process simpler.
- You won’t find extras either. There aren’t any with a Glycemic-Index Diet.
- Feeling full shouldn’t be a problem. Nutrition experts emphasize the importance of satiety, the satisfied feeling that you’ve had enough. Because low-GI foods – especially beans, produce, and whole grains – are thought to take longer to digest, you’ll likely keep hunger pangs at bay.
- Taste is up to you. You’re preparing the food so if it doesn’t taste good, you know who to blame.
How much should you exercise on Glycemic-Index Diet?
The GI approach deals only with ranking carbs. But that doesn’t mean you shouldn’t exercise.
No matter the diet, the more you move, the quicker you’ll see the pounds come off – and reduce the risk of certain chronic diseases. Adults are generally encouraged to get at least two and a half hours of moderate-intensity activity (like brisk walking) each week, along with a couple of days of muscle-strengthening activities. The Centers for Disease Control and Prevention offers tips to get you started.