Reviews of the Thermogenic Impact of High Protein Diets

The thermogenic effect of food (TEF) is the energy required for the body’s digestion, absorption, and disposal of ingested nutrients. The magnitude of TEF depends on the composition of the food consumed. Of the three types of food, the TEF can be broadly summarized as follows:

  • Carbohydrates: 5 to 15 % of the energy consumed
  • Fats: at most 5 to 15 % of the energy consumed
  • Protein: 20 to 35% of the energy consumed

Thus, metabolic processing of protein requires the greatest expenditure of energy, with estimates ranging as high as 35% of the derived total energy being needed for the initial protein breakdown. Dietary fat, on the other hand, is very easily processed, and when turned into body fat, there is very little thermogenic effect, perhaps only 2 or 3%. Finally, the amount of energy required to process carbohydrates falls between that of protein and fat. It is also known that the thermogenic effect of food is increased by both aerobic exercise of sufficient intensity and duration and also by anaerobic weight training.

Upon seeing the above breakdown of the TEF figures for the various classes of foods, one can see why a figure of 10% is generally used to account for the thermogenic effect of food. Thus, for instance if you want to replace 1000 calories burned through activity, you need to eat 10% more, or 1100 calories, to account for the TEF effect. If you eat 1000 calories, 10% of these will be burned off by the thermogenic effect, leaving only 900 calories effectively available for use.

Some diets have been advocated as being effective for fat and weight loss, based on their relatively high proportion of protein. This includes both the Atkins Diet, and some more recent “metabolic diets” such as “Metabolic Cooking” – http://metaboliccookingrevealed.com .

In a thorough meta-analysis of high protein diets, and its effects on weight loss, available at http://www.jacn.org/content/23/5/373.long , (Journal of the American College of Nutrition, 2004), entitled “The Effects of High Protein Diets on Thermogenesis, Satiety and Weight Loss: A Critical Review,” it was concluded that

“Our review suggests that higher protein diets may significantly increase total weight lost and possibly percentage of fat lost when compared to a lower protein diet in the short term. Possible mechanisms include an increased satiety and decreased subsequent energy intake with higher protein diets. All 5 investigations that utilized an ad lib intake found significantly increased weight lost with the higher protein regimens in the short term studies (6 months or less).”

salmon - a good source of protein

Salmon – a food source high in protein

The final conclusion of this review is “Although the optimal amount and sources of protein cannot be determined at this time, the weight of evidence suggests that in dietary practice, it may be beneficial to partially replace refined carbohydrate with protein sources that are low in saturated fat.”

One can thus conclude that diets that include a larger than usual amount of protein may be successful due to the inherent thermogenic effect of protein. Indeed, a diet like Metabolic Cooking can explain its success, at least in the short term, as due to this thermogenic effect of protein. These findings may explain the relatively successful “Paleo Diet,” otherwise called the Cave Man diet.

Causes of Anxiety Disorder

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The connection between anxiety disorders and a sensitized state is a theory explaining panic attacks, developed in the 1980’s by Steven Reiss and Richard J. McNally. They defined this sensitized state as ‘anxiety sensitivity’ and roughly 1,100 published studies have confirmed this theory. In short, Reiss and McNally conclude that a small, but consistent, percentage of the population experience high anxiety sensitivity, making these individuals more susceptible to an anxiety disorder.

An anxiety sensitivity index (ASI) was create as a tool with which people can measure their stress sensitivity using a self-scoring technique. The ASI is used to assess anxiety disorders in many thousands of patients every year.

Nowadays, a comprehensive test, known as the ASI-R, or  ”Anti-Sensitivity Index Revised,” is used to understand the basic dimensions and hierarchical dimensions of anxiety sensitivity. ASI-R includes 36 questions, using a scale from 1 to 5. In ASI-R, 1 represents strong disagreement and 5 represents strong agreement. The middle of the scale signifies neither agreement nor disagreement. The ASI-R has 6 sub-scales which address the following disorder measures:

  • fear of cardiovascular symptoms
  • fear of respiratory symptoms
  • fear of gastrointestinal symptoms
  • fear of publicly observable anxiety reactions
  • fear of dissociative and neurological symptoms
  • fear of cognitive dyscontrol
Claire Weekes Portrait

Dr. Claire Weekes

Dr. Weekes described the sensitized state as a person feeling jittery and susceptible to any mild shock, whether internal (such as a rapid heartbeat) or external (such as a door slamming).

Frequently, individuals with anxiety sensitivity interpret the bodily sensations associated with stress as a sign of impending health problems.  The average person would pay little attention to these sensations. However, an anxiety attack sufferer has a different interpretation. A tight chest becomes a breathing problem. A pounding heart is imagined to be a potential heart attack, and a racing mind becomes transmuted into a fear of mental illness.  The individual with anxiety sensitivity can only react with fear and/or panic.

 For instance, one of the scariest effects of a panic attack is the fear of suffocating or smothering. It’s experienced very commonly during a panic attack, to feel a sense of tightness in the chest and throat. Anxiety develops from the fear that your breathing will stop, and you will not recover. This is, however, irrational. A panic attack can’t lead to a cessation of respiration.

fear

One approach to overcoming anxiety disorders and panic attacks is use of cognitive behavioral therapy (CBT) such as Panic Away. Although a significant fraction of anxiety disorder sufferers do use medications prescribed by their physicians, both the U.S. National Institute of Mental Health (NIMH) and the British National Health Service (NHS) endorse CBT as a preferred modality of treatment for anxiety disorder. 

By employing a cognitive based therapy for anxiety disorder, one also treats the causes of the panic attacks, rather than the symptoms. This is all explained here - http://panicawayrevealed.com .