December 7, 2012
December 12, 2012

Meal Frequency

The optimum number of meals per day has recently become one of the most hotly argued topics in the nutrition field.  From the classic ‘eat every 3 hours’ advice things are now starting to drift towards a less frequent eating pattern.  The two most popular arguments in favour of eating more frequently tend to be:
“eating more often elevates your metabolism”
“skipping meals will slow your metabolism”

Are the above claims true?
Not really.  The human metabolism is a complex and baffling thing that is dependent on several factors; exercise, weight, muscle mass, gender, age etc.  The school of thought that adding or removing one meal per day will change your metabolism substantially is, quite frankly, stupid.

Eating more meals per day WILL NOT elevate your metabolism
The idea that more meals would equate to a higher metabolism came from a misinterpretation of something called the thermic effect of food (TEF).  This is essentially the number of calories your body uses in processing the food you eat.  It tends to average at about 10% of your intake(so your body burns 50kcal of energy in processing 500kcal of food).  Logical science would say eating more frequently means a higher metabolic rate…not exactly.

Compare 2 people; Alan is eating 10 meals per day all exactly 200kcal each, and Jarrett is eating just 2 meals per day of 1000kcal each.  Using the 10% rule, Alan will have a TEF of 20kcal 10 times per day, and Jarrett will have a TEF of 100kcal 2 times per day.  Which gives the same result; 10 x 20=200kcal and 2 x 100 = 200kcal.
Therefore Alan and Jarrett are essentially ‘burning’ the same number of calories processing their food.

Eating less meals per day WILL NOT slow down your metabolism
The idea that leaving longer between meals leads to a slower metabolism comes from the theory that your body enters into ‘starvation mode’ after a period of not eating.  This idea is flawed simply because complete digestion of food normally takes anywhere between 5-7 hours (depending on what you’ve eaten), therefore your body will experience a steady release of nutrients over this time.

To cause a significant decrease in metabolic rate, the human body has to be deprived of calories for an extended period of time.  To put this in perspective, a long term ‘semi-starvation’ study was performed in the 50’s called the Minnesota Study (Kalm and Semba, 2005).   Thirty six lean, healthy men (judged on BMI) had their calorie intake halved for 6 months and their BMR dropped by just 40%.

Other research suggests that only after 5 days of COMPLETE fasting, basal metabolic rate slows by 26% (Ma and Foster, 1986).  During the first 24 hours of fasting your metabolic rate actually INCREASES! (Elia, 1992)

Practical Application
Once you have your calories and macro-nutrients calculated, divide your meals up to suit you!  Don’t like eating in the morning?  Don’t bother.  Prefer the traditional 3 larger meals?  Go for it.  Enjoy smaller meals every few hours?  Do it.  Find out what works for you and your schedule and don’t let your eating patterns rule your day!