Why and How a Low-Glycemic Diet Works for Weight Loss
▶ Understanding how a low-glycemic diet moderates insulin and blood sugar levels
▶ Discovering how a low-glycemic diet acts as a natural appetite suppressant
▶ Staying aware of your calorie intake while enjoying low-glycemic foods
▶ Making the best food choices for optimum health and weight loss
Aquick search for “low-glycemic diet” on the Internet tells you that this diet is being used for weight loss in everything from fad diets to hospital-based programs. Conflicting information can leave you wondering whether a low-glycemic diet is just another fad or a legitimate, evidence- based piece of the weight-loss puzzle. This chapter highlights several reasons why and how a low-glycemic diet works for weight loss as part of a complete dietary plan — one that includes calorie control, lots of fruits and veggies, and an appropriate intake of healthy fat and lean protein as well.
Regulating Insulin and Blood Glucose
A low-glycemic diet helps regulate insulin and blood glucose levels that become unstable due to either a health condition or consumption of an excess amount of carbohydrate calories. Anytime you eat foods containing carbohydrates, your body naturally breaks those carbs down into blood glucose (blood sugar), releasing insulin in the process. Insulin acts like a key that unlocks your cells’ doors to allow blood glucose to enter in and provide your cells with energy (see Figure 3-1).
Even though insulin transports blood glucose to your cells, your body doesn’t turn all of that blood glucose into energy at once. When blood glucose levels rise above normal, insulin signals your liver, muscles, and other cells to store the extra. Some of this excess blood glucose gets stored in your muscles and liver as glycogen, and some of it gets converted to body fat.
Regardless of whether blood glucose is being spent or stored, the influx of blood glucose in your blood can create spikes and crashes depending on what you eat. This process leads to food cravings, moodiness, and fatigue — all of which can make weight loss difficult to accomplish.
In the next sections, I explain how following a low-glycemic diet can reduce the excess fat your body may be storing and positively affect your food cravings.
Keeping blood glucose levels down
Low-glycemic foods play an important role in keeping blood glucose levels down. Your body coverts these foods into blood glucose more slowly and over a longer period of time. That means your body needs less insulin to get the energy into your cells, so your pancreas is spared from being over- worked. It also means there’s less excess insulin just hanging around as fat storage. That’s a plus for weight loss if I ever heard one!
High-glycemic foods, on the other hand, get converted to blood glucose very quickly, causing a rush of blood glucose into the body in large amounts. The result? You feel satisfied and revived for about 30 minutes following a high- glycemic snack, but after those 30 minutes are up, you start to feel fatigued and hungry all over again. Eating more low-glycemic foods helps reduce fatigue and hunger and prevent chronic high blood sugars.
Counteracting insulin resistance
Extra blood glucose (blood sugar) typically gets converted to body fat when you’ve eaten too many calories. Although this process happens to everyone, it may be more challenging for individuals with insulin resistance, a condition in which a person has a diminished ability for his blood glucose to respond to the action of insulin, causing the pancreas to secrete even more insulin to compensate (see the following figure). Many individuals, particularly those with prediabetes, diabetes, metabolic syndrome, or Polycystic Ovary Syndrome, have some varying degree of insulin resistance, which causes their bodies to store more calories as fat when their insulin levels are consistently high.
Warning: If you’re overweight, you may have a small amount of insulin resistance without even
knowing it. Individuals who are overweight, especially those who carry a lot of belly weight around the middle, are at a higher risk for being insulin resistant, a fact that explains why weight loss can be a little more challenging for these folks.
Researchers are currently studying the effects of a low-glycemic diet to see whether it enhances weight loss by helping individuals have better control over their blood glucose levels. Although many studies show promise, the official verdict is still out. No study has con- sistently shown that a low-glycemic diet helps healthy people lose more weight than your aver- age calorie-restricted diet. This fact just means more research is needed, especially among people who have known insulin resistance.
What’s wrong with chronically elevated blood sugars? Over time, too much sugar in the blood for too long can damage the blood vessels and nerves, leading to kidney disease, blindness, nerve damage, heart disease, and foot problems.
Controlling food cravings
Food cravings occur for many reasons, both physiological and psychological, but one core cause of food cravings is erratic blood glucose levels. When your body’s blood glucose levels go through high spikes throughout the day, you can wind up feeling hungry — hence the unwanted yet nagging food craving.
Imagine facing a busy day at work and getting the kids off to various appoint- ments. You don’t have time for more than a couple handfuls of pretzels as you race from work to pick up your kids. Even if this was an adequate snack calorie-wise, you’d likely feel starving in an hour or so. Why? Because pretzels are a high-glycemic snack that sends your blood glucose levels spiking only to drop off quickly shortly afterward.
Often food cravings go hand in hand with low blood glucose levels. Rather than wanting a healthy snack, you may be craving something sweet or starchy as your body tries to compensate for its low blood glucose. This cycle occurs daily for many people, and it’s not just limited to snack time. Breakfasts, lunches, and dinners that are overloaded with high-glycemic foods can also send your blood glucose levels sky-high.
To keep your food cravings under control, follow these two simple steps:
✓ Choose low-glycemic foods for your meals and snacks. (Refer to Appendix A to determine which foods are low-glycemic.)
✓ Match these foods with protein and fat sources.
In the earlier pretzel example, a better snack choice would’ve been an apple with an ounce of nuts. The apple is a lower-glycemic choice that creates a slower blood glucose response in the body. Balancing protein and fat with the nuts helps you feel fuller for longer so you don’t need to raid the refrigerator for high-sugar snack foods when you get home. (See the later “Eating More of the Right Foods to Lose More Weight” section for more on the weight-loss benefits of a little protein and fat.)
For ideas on finding balance in your meals and snacks, flip to Chapter 9.
What about supplements for blood glucose control?
Many supplements that tout better blood glucose control are currently on the market, but do they really work? That’s the question. This sidebar presents a quick summary of some popular supplements so you can make the best decision about whether they’re right for you. Remember: Even a “natural” supplement can interfere with some health conditions and medications, so talk with your doctor before trying any of the following supplements:
✓ Alpha-lipoic acid (ALA) is an antioxidant that protects against cell damage. It’s found in foods such as broccoli, spinach, and liver. ALA has been researched for its effect on insulin sensitivity and blood glucose metabolism. Some studies show benefits, but more research is needed to confirm these findings.
✓ Chromium is an essential trace mineral that the body needs to function properly.
It’s found in meats, whole-grain products, fruits, vegetables, and some spices. Chromium supplementation has been studied for its effect on blood glucose control. Although it’s a fairly popular supplement, the research findings have been mixed, and some studies have been poorly designed. More high-quality research is needed to fully understand chromium’s effect on blood glucose control. Warning: Chromium in high doses can lead to kidney problems. Be sure to talk to your doctor before taking these supplements to guarantee you’re taking the proper dosage.
✓ Omega-3 fatty acids are fatty acids that come from fish, canola oil, and walnuts.
So far little evidence shows that omega-3s have an effect on blood glucose, but there is significant research on omega-3s’ effect on heart health and depression. Consuming fish two to three times a week will give you an adequate supply of omega-3s, but low- to medium-dose supplementation is also a safe choice. Just be sure your fish oil sup- plements have good quality control so they aren’t contaminated with mercury or PCBs. Warning: Fish oil can be a blood thinner, so talk to your doctor if you’re taking medication that may interact with it.
✓ Cinnamon is a commonly used spice. The active ingredient, hydroxychalcone, may enhance the effect of insulin, helping to promote blood glucose uptake into cells and tissues. Although some studies show that cinnamon has a positive effect on blood glucose control, others show no significant differences. This is yet another supplement that needs further testing. Cooking with cinnamon or drinking cinnamon tea is completely safe and a good way to test this spice’s effects out on yourself. But be careful when using cinnamon supplements because many may not be the right type of cinnamon and some may interact with certain medications.
Suppressing Your Appetite Naturally
A low-glycemic diet not only helps you manage blood sugar and insulin levels but it also serves as a natural appetite suppressant. Who needs scary over- the-counter diet pills when you can just use food? Better yet, incorporating low-glycemic foods helps you deal with a reduced calorie intake so you don’t feel starved all day. The following sections highlight the two main reasons a low-glycemic diet can work to control your appetite.
Feeling fuller with fiber
Fiber is nature’s natural appetite suppressant. It provides bulk and slows down digestion to help you feel full for a longer period of time. So what does fiber have to do with a low-glycemic diet? Well, many low-glycemic foods are also higher in fiber.
Not all low-glycemic foods are high in fiber, but you may naturally increase your fiber intake as you begin following a low-glycemic diet. (To discover foods that are both low-glycemic and high in fiber, head to Chapter 2.)
Another reason why fiber makes you feel fuller is that high-fiber foods take longer to chew, causing you to take a little longer with your meal. Your brain needs 20 minutes before it can register that you’re full, and many people can wolf down a second helping before that 20-minute mark is up. High-fiber foods take a bit more time to get through.
Bumping up your fullness hormones with low-glycemic foods
Appetite is controlled by an intricate dance of hormones that trigger hunger and fullness. Have you ever felt that “way too full” feeling for hours after a big meal? You know, like when you’ve eaten a huge Thanksgiving dinner and all you want to do is curl up on the couch like a beached whale afterward. That feeling is the effect of your fullness hormones.
One of these fullness hormones, called GLP-1, has been shown to be of particular importance in preliminary studies with a low-glycemic diet. GLP-1 is one of two hormones that works by telling your brain you’ve had enough. It really brings things to a halt by telling your stomach to stop moving anything along to your intestines until what’s already there has been broken down.
Early in 2009, researchers from King’s College in London took a closer look at GLP-1 in respect to a low-glycemic diet. Volunteers who ate a low-glycemic breakfast ended up with 20 percent higher levels of GLP-1 in their blood after- ward compared to those who ate a high-glycemic breakfast. This preliminary study shows a direct correlation between a low-glycemic diet and GLP-1, but more research is needed to confirm this finding.
Until that research is available, why not conduct your own experiment? Here’s how:
1. Maintain your current diet for several days and keep food records.
2. Rate your level of fullness/satisfaction on a scale of 1 to 10 (with 1 being hungry and 10 being full) two to three hours after a meal or snack.
3. As you begin including more low-glycemic foods in your meals, note any differences in your overall hunger/fullness levels.
Combining Low-Glycemic Foods with Calorie Awareness
Following a low-glycemic diet isn’t a stand-alone solution for weight loss. Like it or not, you still need to pay attention to the amount of calories you take in each day.
If you eat a low-glycemic diet that’s still high in calories, you aren’t going to get very far with your weight-loss goals. A low-glycemic diet is an important piece of the weight-loss puzzle, but it’s not the solution to the puzzle.
Successfully losing weight requires a holistic approach that includes eating a combination of low-glycemic carbs, healthy protein, and fats; counting calories; exercising; and doing what you can to pump up your metabolism.
In the sections that follow, I explain why paying attention to calories is still essential on a low-glycemic diet and how to get the most out of your daily calorie allotment.
Understanding why calories still count
Calories are always going to be one of the most important aspects of weight loss. If you consume more calories than your body can convert into energy, your body turns that unspent energy into body fat and stores it somewhere.
Think of it like a car. Gasoline is similar to calories in that it provides energy for the car to function just like calories provide you with the energy you need to function. If you fill a car’s gas tank past capacity, the extra gas overflows onto the ground. Unfortunately your body’s overflow system doesn’t just land on the ground; it winds up on your thighs, your rear, your stomach, and wherever else your body deems fit to store fat.
To lose weight effectively, you need to reduce your calorie intake through dietary changes and exercise. Table 3-1 gives you an idea of the calorie deficit needed to lose a specific amount of weight.
Cutting back on your calorie intake doesn’t mean you need to diligently count calories. Who in his right mind actually wants to do that all day every day? Instead, you just need to make small changes that lead to a calorie deficit.
Adopting a low-glycemic lifestyle is one of those changes because many low-glycemic foods are lower in calories. People who start choosing lower-glycemic foods tend to naturally lower their calorie level without even having to think about it.
Following are a few examples of how switching to a low-glycemic diet can impact your calorie level:
✓ Choosing a side salad with your sandwich rather than a small bag of potato chips saves you 50 to 100 calories.
✓ Switching from a large bagel (about 4 ounces) with cream cheese for breakfast to 1 cup of low-glycemic cereal with milk saves you around 200 calories.
✓ Skipping the baked potato with all the fixings at your steak dinner and replacing it with steamed broccoli saves you around 300 calories.
See? Changing even one meal a day to incorporate low-glycemic foods can be enough to impact your weight loss each week. These changes may seem small, but they add up to big calorie deficits when you stick with them over time.
Knowing that low-glycemic doesn’t always mean low-calorie
Although it’d be great if eating low-glycemic foods always resulted in lower calorie levels, it doesn’t always work out that way. The calorie deficits you experience on a low-glycemic diet really depend on what your diet looked like before. If you’re exchanging a lot of unhealthy or high-calorie choices for more healthy, low-calorie foods, then yes, you may see a difference in your calorie level. However, if you already eat a fairly healthy diet and you’re simply replacing your high-glycemic grains and veggies for their lower- glycemic counterparts, you won’t see much of a difference in your overall calorie level. For example, brown rice is lower-glycemic than jasmine rice, but both contain the same amount of calories.
Don’t forget that some treats, such as chips and even some types of candy, have a lower glycemic index but are still high in calories. For example, Peanut M&M’s are low-glycemic, but one package costs you 243 calories — that’s a lot for a small treat.
Beware of fad diets and messages that simplify the glycemic index diet too much. Just because you’re eating low-glycemic foods doesn’t mean you can forget all you know about good nutrition. A low-glycemic diet should be looked at as a new way to make the best choices for carbohydrate-containing foods — not as a stand-alone solution for weight loss. When it comes to weight loss, calories still matter.
Keeping portion sizes under control
Even if you’re swapping your favorite high-glycemic foods for healthier low- glycemic options, if you regularly eat inappropriate portion sizes, you won’t see success. I can’t tell you how many times I hear people saying, “As long as it’s low- glycemic, you can eat as much as you want.” That’s simply not the case.
Eating inappropriate portion sizes hurts you in two ways:
✓ Low-glycemic foods can become high-glycemic foods if you eat too large of a serving. The low-glycemic status of many foods is dependent on you consuming the right portion size, meaning if you eat more than that amount, your glycemic load will add up. So if you eat two servings of pasta rather than one, you wind up with a higher glycemic load for that whole meal. (I explain glycemic load in detail in Chapter 4.)
✓ More food equals more calories. Adding more calories with large portion sizes will defeat your efforts at weight loss quickly. Whether or not your calories are coming primarily from low-glycemic foods, eating too many of them raises your insulin levels and causes you to gain weight.
Portion sizes are probably one of the biggest culprits in weight gain. People are eating larger portion sizes than ever these days, a fact that correlates directly to the rate of weight gain in many countries.
For some guidance on the appropriate portion sizes for several different foods, flip to Chapter 9.
Eating More of the Right Foods to Lose More Weight
If you want to keep your body working at peak performance to ensure an increased metabolism, improved health, and success with long-term weight loss, then you need to make the foods you eat work for you. In other words, aim to get the most nutritional bang for each bite. The following sections help you pick the foods that can add balance, vitamins, and minerals to your diet.
Choosing lots of fruits and vegetables
Two food groups are generally safe to eat in greater amounts when you want to lose weight: vegetables and fruits. These foods (particularly vegetables) contain lower calorie levels and lower glycemic loads than most other foods. In fact, most vegetables aren’t even measured for their glycemic index/load because the amount of carbohydrates in them is so low (approximately 5 grams on average). As for the calorie factor, a whole cup of raw vegetables or a half cup of cooked vegetables is, on average, a mere 25 calories. That’s a lot of food for such a small calorie amount! On the fruit side of things, most fruits tend to have a low glycemic load, and one small piece averages out to 60 calories. Sure, that’s not as low as the veggies, but it’s still lower than many other food groups.
When you want to lose weight, you can choose to either have tiny portion sizes of high-glycemic foods or pump up the volume with fruits and vegetables and still maintain a lower calorie level. Consider the following calorie information:
1 cup of steamed broccoli = 50 calories
1 cup of fruit = 60 calories
1 cup of pasta = 160 calories
1 cup of ice cream = 340 calories
As you can see, for the same volume of food, you can consume far fewer calories by eating more fruits and vegetables. The beauty is that most of the foods in these two food groups end up on the low-glycemic food list! (See for yourself in Appendix A.)
The following examples illustrate how you can cut the calorie level of your dinner and dessert with some simple, low-glycemic food swaps:
Dinner
Grilled garlic chicken served over 11⁄2 cups of pasta = 345 calories Grilled garlic chicken served over 1⁄2 cup of pasta with 1 cup of broccoli,
red pepper, and snow peas = 235 calories Total savings: 110 calories
Dessert
1 cup of ice cream with chocolate sauce = 440 calories
1⁄2 cup of ice cream with 1⁄2 cup of fresh strawberries = 230 calories Total savings: 210 calories
By incorporating more low-glycemic fruits and veggies, you get the same volume of food on your plate but with fewer calories, a lower glycemic load, more fiber, and more nutrients. Not bad for a simple switch!
You can also use vegetables and fruits to increase your overall volume of food for the calorie level. For example, you can have a large salad with 3 cups of mixed greens plus 1 cup of assorted veggies (including tomatoes, peppers, and cucumbers) with grilled chicken and light vinaigrette dressing for around 250 calories. Compare this meal to the grilled chicken over 11⁄2 cups of pasta for 345 calories. You get around 41⁄2 cups of food for the salad meal compared to around 2 cups of food for the pasta and chicken dish. Eating more vegetables and fruits at a meal means you can have more food for fewer calories. That’s a great plan if you ask me!
Including healthy fats and protein
Of course, you can’t pursue weight loss and health without taking a look at all the foods you consume, including your protein and fat sources. These are two of the nutrients that make up the Big Three of calorie sources (carbohydrates being #3). Not only that but they also help you feel full and give you long-term energy.
Choosing lean-protein foods is essential for weight loss and general health. Some examples of lean-protein sources are skinless chicken breasts, lean cuts of beef and pork, egg whites, fish and shellfish, and soy foods. You also need to eat fat. Believe it or not, fat is healthy when it’s the right kind and when you consume it in moderate amounts. Look for unsaturated fat sources, specifically oils, seeds, nuts, nut butters, olives, and avocados. Do your best to avoid saturated and trans fats such as butter, cream, lard, and hydrogenated oils.
Consuming a protein source and a fat source at each meal is a great way to slow down your body’s digestion and conversion of carbohydrates into sugar to provide long-term fullness and nutritional health . . . both of which are keys to long-term weight loss!
Eating the right amounts of low-glycemic fruits and vegetables along with portion-controlled low-glycemic starches is great, but if you’re pairing those foods with excessive amounts of butter, oils, or high-fat meats, your hard work may all be for naught. Pay attention to your portion sizes. Fats in particular are very calorie dense, so keep a close eye on ’em. One teaspoon of oil, 1 tablespoon of nut butter, or six almonds, for example, is plenty.
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