Amy P. Campbell, MS, RD, CDE, and Richard S. Beaser, M.D.
The weeks excerpt answers the following questions:
- How important is timing of meals?
- How flexible can meal timing be?
- What is the traditional gauge to measure obesity?
- What are the forces that can affect the ability to achieve a desired weight?
- How effective is providing a weight-loss goal?
- Timing of Eating
Timing of Meals
Though the timing of food consumption is important, newer pharmacologic treatment agents have made the need for precision of meal timing less crucial.
For people whose diabetes is not insulin-treated, the total daily caloric intake should be modified based upon the person’s individual goals. For those people who tend to skip meals, distribution of calories throughout the day may need to be addressed. For people treated with insulin, food intake should coincide with the peak action times of the insulin. Typically, traditional diabetes meal plans often included several snacks consumed at insulin peak times. However, the newer insulin analogs and insulin treatment designs allow more flexibility. The rapid-acting insulins that peak sooner and mimic the timing of natural insulin, such as lispro, aspart, and glulisine, are being combined with effectively designed basal insulin programs using repeated injections of intermediate insulin (NPH), or more commonly the long-acting insulins glargine or detemir (see Chapter 9). These basal programs recreate the smoother, peakless, natural basal effects more precisely and avoid having large quantities of intermediate or long-acting insulin peaking at once. Therefore, meal timing can now be more flexible, as it is not as crucial to match a meal with the time that a large insulin dose may be having significant action.
Obesity is epidemic in today’s society among people with and without diabetes. While medical conditions may be the cause of obesity in a small minority, the basic reason that most are obese is that they consume more calories than they burn for energy. Obesity is becoming more of a problem in children, as well, and the result is that the incidence of type 2 diabetes in this young population has increased markedly in recent years. Contributing to this epidemic may be factors such as cutbacks in funding for school physical education, too much television, or the popularity of computer and video games. The 12 year old of a previous generation spent a weekend afternoon playing outside with friends, while 12 year olds now are more likely to spend that afternoon sitting at the computer, online with friends. To make matters worse, many eat out of habit and nibble while sitting by the computer, by the television or when doing homework.
Body mass index (BMI), which evaluates weight in relation to height, is the traditional gauge to measure obesity. It is defined as the body weight in kilograms divided by the square of the height in meters, or the weight in lbs multiplied by 703 and divided by the square of the height in inches.
As BMI levels increase over 25, so, too, does the health risk (see Table 5-1). According to the National Heart, Blood and Lung Institute (NHBLI), "overweight" is defined as a BMI of 25 to 29.9 kg/m2, "obesity" is defined as a BMI >30 kg/m2 and severe obesity as a BMI>40 kg/m2.
Another key measure in weight and body-fat assessment is waist circumference. It is now known that waist circumference is a stronger predictor of cardiovascular disease (CVD) outcomes than BMI. Measuring the waist circumference gives an indication of the extent of abdominal fat, or central adiposity, which is fat that is more "metabolically active." A high amount of abdominal fat predisposes a person, not only for heart disease, but also for type 2 diabetes, high blood pressure and dyslipidemia as well. American men with a waist circumference of 40 inches or greater, and American women with a waist circumference of 35 inches or greater are at increased risk for CVD. In other ethnic groups such as Asians, the risk starts to increase at much lower waist circumference.
Waist circumference, along with BMI, blood pressure, blood glucose and blood lipid levels, should be measured in a primary care setting to identify those patients who are at cardiovascular risk.
Unfortunately, in many cultures obesity is confused with prosperity and good health. Obesity can also run in families, both through inherited tendency and also by learned eating habits and ethnic diet preference. Psychological issues can also contribute. Loneliness, depression, and anxiety can lead people to seek gratification by eating. Specific considerations for developing a weight loss program will be discussed later in this chapter.
To lose weight, people must either take in fewer calories or burn up more calories, or both. Exercise alone does not usually result in significant weight loss; it is effective when accompanied by a lower caloric intake and behavioral modification. With weight loss, insulin works more effectively and less insulin is needed. Triglyceride levels also decrease, and glucose tolerance improves, signifying improved diabetes control. The amount of energy used and the basal metabolic rate decrease with weight loss as a result of a low-calorie diet alone; this can slow down metabolism and may cause a "plateau" in weight loss. Adding exercise, especially with a relatively higher protein intake usually makes the difference by maintaining lean muscle mass. To summarize this dual pronged approach to weight loss, Dr. Joslin, in a humorous vein, has been quoted in many past publications musing that one of the best exercises is pushing oneself away from the table before one is full!
Other forces can affect the ability to achieve a desired weight:
- ethnic customs and beliefs
- family habits
- lifestyle factors
- psychological issues
Setting a realistic weight-loss goal is an important part of any weight loss program. Rapid-weight-loss programs rarely work in the long-run and should be avoided or only used in extreme situations. In addition, telling a person who is 50 pounds overweight that his or her goal is to lose those 50 pounds is of little use, as the person will invariably fail because such a goal is overwhelming. Once the initial weight loss plateaus, frustration often leads people to abandon their efforts.
Goals should be short- to medium-term, and realistic. The 1994 nutrition recommendations developed by the ADA changed the way we send messages to our patients about setting unrealistic goals for weight loss.
Moderate weight loss can result in a significant improvement in blood glucose in people with type 2 diabetes who are overweight or obese. It may not even be necessary to achieve "desirable" body weight — in many instances, a 10 to 20 pound weight loss (7 to 10% of body weight) is sufficient to significantly improve insulin sensitivity and glycemic control. Therefore, achieving a "reasonable" weight (the weight that a patient and provider agree can be achieved and maintained) may be a more realistic goal.
In addition, targets should be designed in steps or increments. For example, a person who is 50 pounds overweight might be given a goal of losing 10 pounds over a 3-6 month period. This goal is realistic and not so overwhelming. In addition, someone 50 pounds above ideal body weight may only need to lose 10 to 20 pounds to have a significant impact on metabolic parameters.
Providing a weight-loss goal is often ineffective if it is not accompanied by recommendations for specific behavior changes. Determine caloric intake levels as previously discussed and then use those levels along with information obtained from the nutritional assessment to design a specific medical nutrition therapy plan.
Next Joslin Excerpt: Initiating Medical Nutrition Therapy
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