Low Carb Diets: Myth or Miracle?
Turn on the television, tune in the radio, or open any magazine and you're bound to bump into a story about low carb diets. Low carb diets have made a come back - and created controversy. What is a low carb diet? Does it work? Will it keep the weight off? To answer those questions, we turned to our Jenny Craig Medical Advisory Board, 7 recognized experts in nutrition, exercise and lifestyle change for healthy weight management.
Carbs 101
Carbohydrates are the body's major energy source, providing the calories not just for running a marathon, but for basic functions like breathing, eating and sleeping. Carbohydrates form the foundation of a healthy menu. They can be found in whole grains, corn, potatoes, pasta, rice, vegetables, fruits and milk/yogurt. Carbohydrates also include added sugars like sucrose (table sugar), honey, cornstarch and corn syrup. To be used by the body, all carbs must be broken down into the simplest form, glucose.
What Counts as Low Carb?
Because there is no FDA-approved definition of "low carb," food manufacturers can decide how much and what kind of carbs or carb replacements they want to put into a product. As for low carb diets, many start out with as little as 20 grams of carbohydrate per day and build to no more than 40 grams on an ongoing basis. This is far below the 130 gram daily minimum recommended by most health experts.
The Rationale for Low Carbs
Low carb diets are based on the mistaken belief that carbohydrates raise blood insulin, which then leads to weight gain. The truth is, it's not carbs, but extra weight from excess calories, that boosts insulin. And weight loss, regardless of what type of calories you eat, will bring insulin levels down.
Why People Lose on Low Carb Diets
In the initial phase of carbohydrate restriction, most of the weight loss results from the breakdown of glycogen, the body's stored form of carbohydrate. Glycogen holds water and its breakdown results in what appears to be dramatic weight loss. Just remember, most of that loss is from water, not fat. Over time, glycogen stores are used up. The body turns to protein and fat for fuel, and the rate of weight loss begins to slow down.
Can Certain Carbs Make You Gain?
One variation on the low carb diet uses a rating scale called glycemic index to separate out "good" carbs from "bad" ones. Glycemic index is a measurement of how quickly carbohydrates in food are turned into glucose. The theory is that high glycemic index foods are more quickly converted to glucose, and more likely to be stored as body fat. The theory also says eating high index foods leaves you feeling hungrier, and so you are more likely to overeat.
Glitches With The Glycemic Index
The problem with the theory is that research doesn’t support it. Even people with diabetes who regularly monitor their blood sugar levels are not advised to use the index. Studies have not confirmed that eating specific foods negatively affects insulin levels, blood sugar control or even hunger.
Another problem with glycemic index is that it is not very practical. Glycemic index is based on the score of a single food. However, we usually eat foods as a combination or part of a meal, versus alone. Also, the index is based on factors like ripeness and how a food is prepared. So, a ripe banana has a different rating than a green one, and a mashed potato has a different rating than a baked one. Finally, relying on the index alone for food choices may mean eliminating some higher-rated, but nutritious foods - like watermelon or corn - from your menu.
Given its lack of scientific proof and practicality, most health experts do not recommend glycemic index as a tool for meal planning.
It's Calories, Not Carbs, That Cause Weight Loss
It’s true that some short-term studies have shown that at three and six months, low carb diets result in more weight loss than conventional low-fat/high carb diets. The reason is, when given unrestricted calories, low carb eaters tend to eat fewer calories than high carb eaters. Regardless, researchers say it’s the reduction in calories, not the carbohydrates, that results in weight loss. When low and high carb eaters are placed on the same calorie level, there is no difference in weight loss.
Low Carb Diets Don't Last
Research shows that low carb dieters begin to fall off their diets at about six months – at one year, a study showed they had the same amount of weight loss as people on other low calorie diets. The latest research confirms past research – drastic diet changes don’t stick over time. Most of us find it easier to follow a plan that includes moderate amounts of the foods we typically eat.
The Downside of Cutting Carbs
For those who are able to follow a low carb diet for more than a few weeks, it’s important to consider long-term effects on health. Low carb diets restrict fruits, vegetables and whole-grains, the very foods that lower risk for heart disease and certain cancers.
Also, while low carb diets can produce a short-term drop in cholesterol, experts say it’s not the diet, but weight loss that gets the credit. And over time, no one knows the effect of eating 60% of your calories as fat and 20% of them as saturated fat on heart health and cancer risk.
The Key to Calorie Control is Portion Control
If research hasn’t proven that it’s carbs that count, then what it has proven is that calories do. Perhaps one of the most effective tools for controlling calories is a meal replacement – a pre-portioned entrée or snack. Portion control, using meal replacements, aids both weight loss and weight maintenance. Because people tend to eat a set volume of food, the visual of a pre-portioned meal acts as a signal to start-and-stop eating. That makes it easier to control calories – the ultimate determinant of weight loss.
Satisfaction Matters Too
Satisfaction is a complex issue. It involves psychological factors like the pleasure of eating favorite foods or enjoying a meal with family, as well as physical responses to specific food components. Often, a portion-controlled amount of a favorite food is “just enough” because it was what you were hungry for.
When it comes to the physical side of satisfaction, moderate amounts of lean protein may help curb hunger. However, fruits, vegetables and whole grains offer both fiber and volume – so they are satisfying for fewer calories than many other foods.
Balancing Health With the Pleasure of Eating
When you focus on calories, you don’t need to avoid entire food groups, buy special low carb products or give up your favorite foods in order to lose weight. By balancing your choices, you can continue to enjoy your personal eating style as you enhance your health.
The Jenny Craig Menus highlight balance, variety and moderation in food choices. Based on the guidelines of multiple health organizations, Jenny Craig Menus offer a calorie distribution of 55-60% carbohydrate, 20-25% protein and 20-25% fat. They also reflect the US Dietary Guidelines with an emphasis on fresh fruits, vegetables and whole grains as a complement to Jenny Craig’s portion controlled entrées and snacks.
Recommended % of Total Calories
Institute of Medicine
American Heart Association
Jenny Craig
Carbs
45-65
55
55-60
Protein
10-35
15
20-25
Fat
20-35
30
20-25
Jenny Craig: A Total Solution
Ultimately, the question to ask is not “what is the most effective weight loss diet?” The more important question is “what is the most effective weight management diet,” and the answer is…it’s not a diet, but lifestyle. Science shows that the true solution to weight challenges is a comprehensive one. It’s a food/body/mind approach that includes a nutritious menu, a personalized activity plan and the motivational support to maintain positive changes. It strikes a balance between health and your personal tastes. That’s the program you can enjoy for life. That’s the program you get at Jenny Craig – it works!