1. The Glycemic Index Diet says you'll lose weight healthily and easily -- without going hungry. Ageless wonder Sharon Stone is a firm believer.

The truth: Foods are assigned numbers according to their glycemic index (GI). The higher the number, the greater the blood-sugar response. "Weight-loss diets claim that low-GI foods, such as lentils, can help control your appetite because they’re digested and absorbed more slowly," says Kristin Hildahl, a registered dietitian with Nutrition by Design in Winnipeg. "But more research is needed."

Keeping your blood sugar on an even keel may translate into fewer hunger pangs and love-ins with the office candy jar and, ideally, some weight loss. Lots of low-GI foods are rich in nutrients, unrefined and high in fibre, says Hildahl. "The problem is, not all of them are." Higher-fat foods will have lower glycemic effects (french fries can have a lower GI than a baked potato), so the healthier choice may be trumped. And GI charts usually list single foods, yet Ali J. Chernoff, a registered dietitian and founder of Nutrition at Its Best in Vancouver, says, "as soon as you eat two foods together, the GI changes."

The bottom line: "It's based to some extent on healthy choices, but depends on how the person uses it," says Hildahl.

2. The Raw Food Diet is a plant-based diet that favours foods in their natural right-off-the-tree state, with nothing cooked above 118°F (48°C). Demi Moore and model Carol Alt are both fans.

The truth: Based on the notion that good-for-you food enzymes are destroyed when overheated, this diet keeps it cool with an eating plan full of raw veggies and fruits. Though some people follow this diet from a vegan perspective, cheeses and milks from unpasteurized sources can be added, as well as raw fish (sashimi) and raw beef (carpaccio). Hildahl is concerned that consuming raw eggs or raw milk "can put you at risk for foodborne illness."

She also points out there's some evidence that heat can actually increase the bioavailability of nutrients, allowing them to be more easily absorbed and used by your body. As well, the diet is low in vitamin B12; not getting enough of this heart-healthy vitamin can put you at risk for high cholesterol, says Chernoff.

The bottom line: If extensive daily food prep is your default time-killer, and seeking out elusive foods like raw milk is fun for you, sign on the dotted line.

Page 1 of 4 -- Find out the truth about the Dukan Diet and the Mediterranean Diet on page 2

3. The Dukan Diet skyrocketed with intrigue when rumours swirled that Kate Middleton and her mom were slimming down care of Dr. Dukan's bulge-busting bible. Word has it Jennifer Lopez is also a fan.

The truth: Pegged as "the real reason the French stay slim" by creator Dr. Pierre Dukan, this diet is divided into four phases: Attack, Cruise, Consolidation and Permanent Stabilization. Attack Phase restricts food intake to one macronutrient – protein – to provide your energy. You remain on each phase until you hit your target weight, downing two tablespoons of oat bran and walking 20 minutes a day.

Carbohydrates come later, in Consolidation Phase, when you're allowed two celebration meals per week. You can eat what you like, so long as you stick to one serving and don't eat the celebration meals on consecutive days. "One of the biggest concerns is that your body needs to have some carbohydrates to run efficiently, and without them your body can start to break down muscle," says Hildahl. "When the body is low in carbohydrates, it can lead to a state of ketosis, which can make you incredibly fatigued."

The bottom line: "I don't think it promotes healthy and sustainable weight loss," says Hildahl.

4. The Mediterranean Diet is known for its emphasis on improving your health (the risk of heart disease, diabetes, cancer and Alzheimer's disease all decrease dramatically on this plan). This diet's rep is solid. Penelope Cruz is a fan of what she calls the "good food diet."

The truth: Picture the leisurely way of dining in Italy and Greece, where people take time to enjoy their food rather than "eating over the kitchen sink before driving the kids to hockey practice," says Hildahl. The focus is on unprocessed, plant-based foods such as fruits, vegetables, nuts, legumes and whole grains. The fats that are allowed are unsaturated (au revoir, butter; hello, olive oil), exercise is encouraged, and red meat and wine are consumed in moderation. Chernoff thinks the high intake of veggies, fruits and legumes is good, but doesn't like suggesting alcohol to people who don't normally drink. She also warns about portion sizes. "Tree nuts are healthy, but 23 almonds equate to a full serving of meat."

The bottom line: "Its foundation is focused on healthy eating," says Hildahl. "It doesn't compete with Canada's Food Guide: It complements it."

Page 2 of 4 -- Learn the truth about the Macrobiotic Diet and the Paleo Diet on page 3


5. The Macrobiotic Diet is loved by the high priestess of pop, Madonna. The American singer and actress loves this lean, green diet.

The truth: This veggie-heavy diet eliminates milk, cheese, yogurt and eggs, says Chernoff. Grains, fish and lots of veggies are the usual suspects. On top of that, consuming plenty of high-sodium miso soup is recommended. The meal plan -- which is low in fat and high in plant-based foods -- is a plus, but the idea of banning supplements is a drawback, says Hildahl, particularly since it can be difficult to get sufficient levels of protein, vitamin B12, iron, vitamin D, calcium and magnesium on this diet.

The bottom line: If you're a meat eater, it doesn't make sense for you to eliminate a food group you enjoy, says Chernoff.

6. The Paleo Diet suggests you channel your inner cavewoman with a back-to-basics approach based on food our foraging ancestors would have eaten. Actress Megan Fox is reportedly a fan.

The truth: Created by Dr. Loren Cordain, professor of health and exercise science at Colorado State University, and a team of scientists and researchers, this plan will have you eating game meats, fish, nuts, seeds and plants. You'll be eliminating sugar, dairy, grains, high-starch vegetables and processed foods from your diet.

Fruits aren't banned, but low-sugar options are encouraged for optimum weight loss (goodbye, grapes). "There are some good aspects of the diet, such as promoting eating more natural, whole foods," says Hildahl. "But you risk not getting enough important nutrients, such as calcium and vitamin D." Dining out may also be challenging, as the plan is restrictive, and access to game meats in certain regions of Canada is limited.

The bottom line: "It's very hard to mimic this diet at home," says Hildahl. "By eliminating both grain, and milk and alternative food groups, it's not very nutritionally sound," adds Chernoff.

Page 3 of 4 -- Check out some of the strangest diets for weight loss on page 4
4 strange diets for weight loss
We reminisce about some of the kookiest diets.

1. The Baby Food Diet
Conceived by Gwyneth Paltrow's trainer, Tracy Anderson, the diet replaces one or two meals a day with blended veggie concoctions to severely restrict your food intake (netting around 14 jars of baby food a day).

2. Israeli Army Diet
Made popular in the 1970s, this diet had zero connection to its peculiar moniker. For eight days, you eat the same food for two consecutive days: apples, cheese, chicken and salad.

3. The Master Cleanse
Mix lemon juice, water, cayenne pepper and maple syrup, then drink six to 12 times a day, avoiding solid foods for 10 days. Beyonce credited this liquid diet with her 20-pound weight loss for her role in Dreamgirls.

4. The Cookie Diet
No, you're not enjoying chewy dough balls warm from the oven. Dieters get a limited number of meal-replacement cookies throughout the day, topped off with a light dinner.

Check out some of the world's worst celebrity diets!

This story was originally titled "The Good, the Fad & the Ugly" in the April 2012 issue. Subscribe to Canadian Living today and never miss an issue!

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