How consistent does my diet have to be in order for me to stay healthy?

There are several different ways of being consistent with your meal plan. And it turns out that all of them can make an important contribution to your health. While many people are not familiar with diet studies in this area, we think that you will find the research results to be both interesting and helpful.

A first way to be consistent with your diet involves the timing of your meals and snacks. Consistent timing pays health dividends—and for a variety of reasons. All of body systems work best in a certain "rhythm." Perhaps the best-known "rhythm" in our everyday experience is the "sleep-wake" cycle. This daily cycle (also called a "circadian rhythm") is linked to our hormone production, cell activities, and also to our digestion. The more consistent that you can be with your food intake during your waking hours, the more in sync your body can become with this daily cycle. Many aspects of your physical health—including your blood sugar regulation and fat absorption—can occur more effectively when you are consistent with your meal timing.

There are also some changes in timing that you would do well to avoid. Since eating later in the evening and closer to bedtime is associated with increased risk of weight gain, obesity, and metabolic syndrome, it's a change in timing worth avoiding. Another change in timing would be postponement of a usual morning breakfast. For most persons, peak glucose tolerance occurs during the morning hours after waking, and being consistent with the clock timing of a regular morning breakfast makes for good "biological timing" as well.

A second way to be consistent with your diet involves the type and variety of foods that you eat. Included in this category would be: (1) the total number of different foods that you eat over the course of a day, (2) the total number of different foods within any given meal, and (3) the total number of different foods within any particular food group. Because the total number of different foods that you consume over the course of a day depends on the total number within each meal (or snack), there have been more research studies about within-meal variety than within-total-day variety. In general, these studies show that we tend to consume more food and more calories from food when a greater-than-usual total number of foods are available within a given meal. A helpful way to think about this research finding is to imagine a cafeteria, buffet style restaurant, or a potluck dinner in which all of the guests have been asked to bring a separate dish. A greater-than-usual number of foods are available in these eating situations, and studies show that overeating is more likely under these circumstances.

Some studies show a very interesting exception to this rule involving vegetables and other nutrient-rich, lower calorie foods. When we limit the total number of different foods that we eat in nutrient-rich, lower calorie food categories—such as vegetables—we tend to increase the total number of different nutrient-poor, higher calorie foods that we eat (including high-sugar and high-fat snacks). In other words, when it comes to vegetables, decreased variety seems to work against us. Let's say that you consistently eat only three to four different vegetables. In this case, studies show that you are likely to benefit by increasing your vegetable variety. Instead of consistently sticking with only three to four different vegetables, you are likely to get increased health benefits by increasing your vegetable variety.

In this vegetable variety context, we also came across a very interesting study on salads. For persons who tended to be influenced by their moment-to-moment eating circumstances, consistent eating of a 100-calorie fresh vegetable salad 20 minutes prior to their dinner meal helped to decrease their total calorie intake at dinnertime. For persons with what the researchers referred to as "flexible restraint" in their food consumption (the tendency to restrict their food amount regardless of the amount or variety available), consumption of a 100-calorie fresh vegetable alongside of their dinner meal was an effective way of reducing overall calorie intake. At WHFoods, we view these specific research findings about salad as being consistent with the overall tendency of vegetable variety to play a uniquely helpful role in your eating approach.

Some final notes here about consistency, frequency of eating, and meal size. While consistency is definitely a plus for your meal plan, studies do not show any absolute best meal pattern. Researchers know that a "wait and gorge" approach does not work, and as a general rule, skipping breakfast and then having one or two larger-intake eating occasions later in the day also tends to be problematic. But when 3-meal, 2-snack patterns are compared to 3-meal, 3-snack patterns, "grazing" patterns with 4-6 eating episodes, and other multi-meal/multi-snack combinations, no single pattern emerges as the absolute best. At WHFoods, we believe that the study findings generally support a morning meal followed by 3-5 eating episodes routine and consistent eating times over the remainder of the day. Based on the research, we encourage you to find a daily pattern within these general parameters that best fits your schedule and personal preferences, and then work on consistency in following it. Consistency will enable your meal plan to become a more familiar part of your everyday experience—as well as your body's physiology.

For more on Great Healthy Eating Habits:

  1. Does Healthy Eating require cooking on a regular basis?
  2. Are grocery lists and organized food plans required for Health Eating?
  3. Does Healthy Eating require three meals each day?
  4. Are snacks a good thing or a bad thing for Healthy Eating?
  5. Does it matter if dinner is the largest meal of the day?
  6. Is it possible to create a well-balanced diet without paying attention to portion sizes?
  7. Is Healthy Eating possible on a tight budget?
  8. Is it okay for me to "eat on the run?"
  9. Just how common is "eating on the run?"
  10. Problem 1 with "eating on the run"—getting distracted from the process of eating
  11. Problem 2 with "eating on the run"—eating too quickly for our body systems:george,421]
  12. References for "Is it okay to "eat on the run?"
  13. References for "Is it okay to "eat on the run?"


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