April 17, 2013
Breakfast skipping compared to high protein breakfast: effect of appetite control in girls.

Are you a girl who regularly skips breakfast? Read on because this well-controlled study is for you.

Introduction:  Breakfast skipping is strongly associated with a greater chance of weight gain.  Furthermore, this trend is also linked to poorer food choices.  Higher protein meals are becoming more popular as a way to improve satiety and appetite control. The purpose of this study was to examine if it is better to skip breakfast or eat one higher in protein in regards to appetite control throughout the remainder of the day.

Methods:  Twenty overweight or obese girls between the age of 15-20 who normally skip breakfast were recruited for this study.  They were tracked for 7 consecutive days and randomized to one of 3 groups: breakfast skipping (BS), a normal cereal meal for breakfast (NP), or a high-protein breakfast (HP) consisting of beef and eggs for breakfast.  Breakfast and lunch were controlled but the rest of the day they were free to eat as much as they wanted. 

Results:  

  • NP & HP led to a 60% reduction in daily hunger.
  • HP lead to a greater increase in total fullness.
  • NP & HP led to a 30% reduction in daily desire to eat.
  • HP breakfast but not the others suppressed an important hunger stimulating hormone (ghrelin) by 20%.
  • HP breakfast but not the others increased an important satiety-stimulating hormone (PYY) by 250%.
  • BS & NP led to greater evening snacking than HP.

Discussion/Conclusion:  A small breakfast of merely 350kcal led to reductions in perceived hunger, the desire to eat, and prospective food consumption.  In addition, it also increased fullness.  What is even more interesting is that the high-protein breakfast group had additional benefits of a reduction in the hunger-stimulating hormone ghrelin, increases in PYY (a hormone that makes you feel fuller), and decreases in evening snacking, particularly of high-fat foods.  The authors note that a limitation of this study was that the breakfast skipping group and the high-protein group had similar total amounts of calories consumed during the day.  Although this study looked at 1-week of food consumption, it is not certain if eating a high-protein meal for longer periods of time (a year or more) would prevent weight gain.  

My input:  The most obvious inferences that the authors draw come from the simple fact that the breakfast skipping group is fasted.  Of course, their perceived hunger/fulness, desire to eat, and prospective food consumption will be higher in the morning because they just woke up.  I think the most powerful part of the study came from the blood draws and the actual measurable physiological significance that a high-protein breakfast did decrease a hormone responsible for making you want to eat and increase a hormone that tells your brain that you are full.That is what truly stands out as powerful rather than all the other results based solely on questionnaires.  For that reason, I’d suggest trying out the high-protein diet over your standard cereal-based breakfast and seeing how it works with your own feelings of satiety throughout the day.

Leidy et al Am J Clin Nutr. 2013 Apr;97(4):677-88

March 5, 2012
Early Stage Subcutaneous Adipose Tissue Remodeling

How would you like to be in a study where they fatten you up for 2 months?  Well, this group recruited volunteers just for that and have provided a significant advancement in what is known about adipose tissue structural changes during the first several weeks of weight gain.

Introduction:  The purpose was to examine molecular changes in adipose tissue structure after 2 months of an overfeeding protocol. 

Methods:  Forty-four healthy males were recruited and told to increase their daily caloric consumption to excess of 760 kcal/day.  To accomplish this, they added 100 grams of cheese, 20 grams of butter, and 40 grams of almonds to their usual diet.  Fat biopsies were taken at 2 weeks and again at the end of the 2 months.

Results:  MRI revealed a significant increase in abdominal tissue volume both for subcutaneous and visceral.  No changes in mean adipocyte (fat cell) surface size or number.  There was a significant increase in the density of capillary vessels.  As you would expect, there was an increase in the number of genes related to fatty acid and lipid biosynthesis.  There was also an upregulation in genes involved in formation of the extracellular matrix and angiogenesis (the creation of blood vessels).

Discussion/Conclusion:  Although there was an increase in genes responsible for storing excess fat, there was not yet a significant increase in size or number of fat cells.  Interestingly, there was an upregulation in capillary density and genes involved in creating more blood vessels to supply the adipocytes.  This could also be a reason why the extracellular matrix was remodeled to create space during initial weight gain.

My input:  There were also some other important molecular pathways that were downregulated in this study but for sake of boring you I decided to leave those out.  I think the main important finding in this study is the disovery of genes involved in creating new blood vessels for the fat cells.  It makes sense if you think about it, that an increase in adipose tissue would demand a larger supply of blood.  Therefore, it is necessary to increase the amount of vessels perfusing the cells.  This group did well in not only showing this in gene arrays but also in histological staining from the fat biopsies.   Another article from a different group found similar results in that the adipose tissue of obese and insulin resistant subjects had larger vessels but fewer capillaries when compared to lean subjects.  I would not be surprised to see pharmaceutical studies in the near future aiming at trying to reduce the amount of blood vessels as a way to amerilorate adiposity.  After that, I would not be surprised if that is soon the next gimmick in supplement companies’ “fat burners”/thermogenic products.

Alligier et al  J Clin Endocrinol Metab. 2012 Feb;97(2):E183-92.

April 30, 2011
The truth.

The truth.

February 28, 2011
Alarming obesity rates

"It is estimated that by 2015, 2.3 billion adults worldwide will be overweight and 700 million will be obese."  

There is still time to change.

Kristin Eckardt et al. Rev Endocr Metab Disord 19 Feb 2011