Thursday, April 15, 2010

The Satiety Effect: Macronutrients and Meal Frequency

Most people know that a diet that is low in carbohydrates is the most efficient and effective way to lose weight, specifically body fat.  Some chalk it up solely to a stabilization and decrease in glucose and insulin levels.  Others say it's only because you eat less on a low-carb diet, therefore it's a simple matter of calories or the resulting calorie deficit.  I believe it's a combination of both and a little more...

The advice I give to frequent email inquiries and clients is keep protein relatively high -- for a variety of reasons.  1) Protein keeps you fuller, longer; 2) protein 'preserves' lean muscle in a calorie deficit; 3) protein has the greatest thermic effect, i.e. it takes more energy for your body to process protein.

With that said, there was a great article published recently in Obesity Journal regarding the effect of higher protein and meal frequency on satiety, appetite, and hormonal responses.  It supports what I believe to be true.  a) keeping protein high is essential in controlling appetite and b) fewer meals is better (which is 'automatic' when using daily IF).

The sample size of the study is small and it was only in obese men, but it applies to both men and women and both lean and obese individuals.  I'm a living, breathing example of this mindset and many I know (who are lean and strong) also believe in a high-protein, low-meal frequency lifestyle.

I'm embedding the study below, but here's a quick summary:
  • Small sample size of 13 obese men.  ( Applicable to both men and women, obese and non-obese based on anecdotal experience and testimonies).
    • One group ate 'normal' protein (defined in study) levels 3 meals/day
    • One group ate 'normal' protein levels 6 meals/day
    • One group at 'higher' protein levels 3 meals/day
    • One group at 'higher' protein levels 6 meals/day
  • PYY is a hormone that measure satiety.  The higher the PYY levels in your body, the more satisfied and fuller you are.
    • PYY levels were highest in the higher protein, fewer meals/day group
  • Ghrelin is a hunger hormone; it's what tells you that you are hungry.  It is a programmable hormone.  For example, if you initiate an IF regimen, your ghrelin will 'relearn' when to tell you that you are hungry.  This is a very cool adaptation the body makes.
    • Ghrelin was lowest in the higher protein, few meals/day group.
  • Both ghrelin and PYY levels were supported by both perceived satiety and hunger.
  • Pre and postprandial hunger, satiety, plasma glucose, and hormonal responses (plasma insulin, ghrelin, and PYY) were assessed.
  • The normal protein, fewer meals/day group showed the greatest rise in plasma glucose and insulin.  This makes sense when you consider that this group consumed more calories AND more carbs per meal.
    • The higher protein, more meals/day group showed the smalled rise in plasma glucose and insulin; this again makes sense for the same reasoning.
  • The study suggested that higher protein intake and fewer meals/day promotes satiety and challenges the concept that increasing the number of eating occasions enhances satiety in overweight and obese men.
    • Supported by the premise that by eating fewer meals per day, but the same amount of protein contributes to increased PYY levels and decreased ghrelin levels.

You can see why I support a higher protein diet coupled with IF and fewer meals/day.  Some days I can only eat one meal because I normally consume 50-60% of my daily required calories in my post-workout meal.  However, I usually eat 2 meals per day over a 6-8 hour period.  One occasion, I'll eat 3 meals but I never consume more than 3 meals/day.

I'll offer this last disclaimer or footnote.  When all is said and done, it's all about calories.  BUT I believe the best, healthiest way to eat is primal-like while utilizing IF and exercise.

Until next time...

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