Wherever you turn there is someone extolling the virtues of eating five to six small meals per day. From doctors to dieticians, from Cosmopolitan to Women’s Health, there has been an explosion of acceptance that frequent small meals are the key to everything from weight loss to lower cholesterol and longevity. Almost all diet books either base their recommendations on this principal or incorporate aggressive snacking as part of their program. Yet remarkably, despite its presentation as dietary dogma, there is almost no science to support such information. In fact it flies in the face of everything we know about metabolism and the hormonal regulation of our energy supplies.
The myth that frequent small meals were the key to weight loss likely arose from two sources. The first involved dietary studies performed in the late 1990’s that showed how frequent small carbohydrate meals could lead to more stable blood sugar and insulin levels along with lower cholesterol. Aimed primarily at diabetics, the concept spread rapidly to normal and then overweight individuals. The second related to research indicating that metabolic rate increased temporarily after a meal. This led to the concept that more meals would somehow “supercharge” the body and allow it to burn off fat. However, that was the ’90’s. Things have changed and new research is available. In addition, the fact that our population is growing steadily larger and unhealthier is certainly a compelling argument against frequent small meals being a dietary panacea!
In order to dispel the myth of frequent small meal eating, consider some of the theories proposed as to why it works. For example, does it really “supercharge” our metabolism? The answer is “no”. While it is true that there is a temporary increase in the metabolic rate associated with the ingestion, absorption and metabolism of food, it only amounts to about 10% of your calorie intake and is independent of meal size. So, whether you eat 3 meals of 900 calories or 6 meals of 450 calories (both totalling 2700 calories) you will only increase your metabolism by 270 calories per day. Unfortunately, the frequent small meal option reduces your leptin levels, which actually lowers your metabolic rate!
Eating numerous small carbohydrate meals during the day may well lead to more stable blood sugar, but at what cost? The persistent secretion of insulin this type of diet causes will actually increase the risk of insulin resistance and metabolic syndrome. The studies that showed how frequent small meals could reduce cholesterol only compared small carbohydrate meals to large carbohydrate meals rather than to balanced protein-complex carbohydrate intake. This latter type of diet achieves stable blood sugars without overstressing the pancreas and also stops the liver from producing cholesterol.
For those on a diet, frequent small meals are offered as the answer to food cravings and satiety. That is a little like trying to get someone to stop smoking while allowing them to light up every time they have a nicotine yearning! Recent research on the real reasons behind hunger and craving relate to neurochemical changes in the brain, abnormal behaviour patterns that need to be changed not reinforced.
Probably the biggest problem with the whole concept of frequent small meals is that they rapidly become frequent large meals. Research shows us that having a snack between meals does not reduce the size of the next meal. In addition, the availability of fast, unhealthy food means that snacks often become highly calorific themselves. Giving an individual carte blanche to eat whenever they like in a society where food is so readily available may be a popular and painless option, but it is highly unlikely to be successful long-term. It will certainly never address the many health issues associated with overeating and a dysfunctional metabolism.
Normal human physiology is not designed for frequent small meals, and remains essentially unchanged from that of our prehistoric ancestors. Neanderthal man was more accustomed to starvation and long gaps between meals than tucking into limitless dinosaur snacks by the fire. As such, humans are hardwired to be hungry and to store food away as fat. The two major hormones, insulin and leptin work together to manage fat stores. After a meal insulin rises for three hours, initially replacing glycogen stores and then shunting any extra calories into fat. As insulin levels fall we become able to access our fat stores as a source of energy. Eating another meal or snack at this point causes a further release of insulin, which not only inhibits our ability to burn fat but also acts as a strain on the pancreas. This secondary rise in insulin is more prolonged, and when the cycle is repeated will eventually lead to hyperinsulinaemia and insulin resistance, forerunners of metabolic syndrome. This pattern additionally leads to leptin resistance resulting in food cravings and a slower metabolism.
For individuals using exercise to lose weight, fat is normally mobilized at two to five times normal with even moderate activity, mostly from the abdominal area. However, even a slight increase in insulin immediately shuts off this process and prevents any access to fat stores. So snacking effectively reverses any weight-loss benefits of your exercise program.
What about an athlete?
An important question is whether these guidelines should be changed in the athletic individual. Current research argues against the concept of “carb-loading” before exercise, but does favour adequate dietary intake to support daily training and recovery by restoring glycogen levels. If the interval between training periods is short (8 to 16 hours) then increasing meal frequency will be necessary to achieve adequate intake. However, in the majority of individuals where there is at least a 24 hour interval between training periods, three balanced protein-carbohydrate meals per day provides the healthiest option.
For the higher-level endurance athlete, adequate calorie intake to maintain appropriate body weight and composition is required. This value will vary tremendously between individuals (the example below is a general guideline). However, achieving intake of 3000-5000 kcal per day with three meals may be difficult and uncomfortable, in which case adding in one or two additional meals (again balanced protein-carbohydrate) would seem reasonable. Similarly, a body-builder requiring protein intake of 1.6 to 1.7 grams of protein per kilogram body weight per day (a regular athlete would require 1 to 1.2 g/kg/day) might have trouble eating that much protein with only three meals.
Meal timing in the elite or high-level endurance athlete is a matter of preference. Some individuals may be able to eat a large meal 1 or 2 hours before training, others may need a series of smaller, easily digested meals. Increased hydration with each meal is essential but content should generally be balanced. The exceptions include intake during exercise, which should be predominantly carbohydrate, and post-exercise meals for individuals training or competing later the same day. In these athletes, early post-exercise carbohydrate intake has been shown to promote faster glycogen synthesis and better endurance recovery.
Daily Energy Intake Example:
70 kg male running 10 miles per day at 6 miles per hour:
Baseline energy: 40 kcal/kg body weight/day = 2800 kcal
Running energy: 0.253 kcal/min/kg weight = 1063 kcal
Daily Total = 3863 kcal
Overall, most athletes should consume their nutritional requirements through three meals and avoid snacks. Hydration should be maintained with all activity and carbohydrate replacement drinks should be reserved for intense training lasting over one hour.
The No-Crave Diet has been developed by Dr. Penny Kendall-Reed and is used extensively in her clinical practise. It is based on up to date research on the neurochemical and hormonal influences behind hunger and food cravings along with sound metabolic principles. The concept that food cravings should be given into by eating frequently is a flawed argument, as it ignores the fact that the same chemical disturbances causing weight gain, obesity and metabolic syndrome are responsible for inappropriate hunger and food craving. Once these are corrected, the desire for frequent snacks and meals is eliminated. The No-Crave Diet offers both weight-loss and maintenance programmes. It is both preventative and therapeutic for type-2 diabetes, high cholesterol and metabolic syndrome. It offers the athlete improved energy, performance and endurance.