The truth about high protein diets

If you are into health and fitness you've probably heard lots about the wonders of high protein diets. Do they really help you lose weight and gain muscle? 

Here you will find facts about high protein diets. 

First of all, what is a high protein diet? 

The recommendation for protein intake for healthy individuals with low to moderate physical activity levels is: 0.8g/kg/day or 10-25% of total energy intake, which means that if an individual weighs 70 kg he should be ingesting 56g of protein per day. 

For athletes the recommendation goes up to 1.2-1.7g/kg/day. 

The maximum protein intake suggested is 2 to 2.5g/kg of body weight per day or 35% of total energy intake (that is 700 kcal out of a 2000 kcal diet). High protein diets are the ones that recommend protein intakes above these requirements. 

Are high protein diets harmful? 

Contrary to what you may have heard, the evidence shows that periodic consumption of high protein diets does not impact negatively renal function, hydration status or bone health in healthy athletes, but extremely high protein intakes are discouraged. 

It is best to consult with a health professional to be sure that it is safe for you. 

Some possible disadvantages...

- They may cause a lower intake of other important nutrients necessary to support training and competition. 

- They are more expensive than other diets. 

- They provide a higher acid load on the body which is not healthy. 

What is the best diet for weight loss?

A healthy diet that produces a negative energy balance, which means: less calories eaten and more calories burned through exercise. 

Are high protein diets effective for weight loss?

Yes, there is strong science based evidence that says that high protein diets are an effective weight loss strategy:

Why?

- Protein has a higher thermic effect than fat or carbs: this means that we burn more calories to digest and absorb protein than carbs or fat. 

- Protein causes greater satiety than fat or carbs: this means that by eating a high protein diet we stay less hungry; this is good because it decreases cravings and binges, common in many low calorie weight loss diets. 

Are high protein diets effective for muscle gain?

Yes, reaserch has shown that protein ingestion in the right amount and timing does maximise the response to resistance training. 

What about timing?

Pre-exercise: If the exercise session lasts less than 1 hour, pre-exercise ingestion may provide a source of amino acids to promote immediate after exercise muscle rebuild. 

During exercise: If the session lasts more than 90 minutes, and/or if you work out more than once per day, protein ingestion during exercise may help maintain protein balance. 

Post-exercise: It is recommended to consume protein immediately after exercise and every 3-4 hours after that over a 12-24 hour post-training recovery period. 

How much?

A serving of around 20-25g of high quality protein to maximise rate of protein synthesis. 

Increasing protein intake up to 40g has no extra effect on muscle protein synthesis and it stimulates amino acid oxidation, which is not healthy. 

What is the best type of protein for muscle gain?

- Animal source protein such as eggs and dairy because they are high in essential amino acids. 

- Protein supplements enriched in essential amino acids (especially leucine) that are easily digested in order tu stimulate muscle protein synthesis after exercise. 

It is recommended to choose whole-food sources of protein low in fat to facilitate protein synthesis and muscle gain while also covering other nutrient needs without gaining fat. 

How does this translate into food? 

Make sure to consult with a nutritionist before starting a new diet plan. 

References:

- Weigle D. et al. A high-protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite compensatory changes in diurnal plasma leptin and ghrelin concentrations. American Journal of Clinical Nutrition. 82(1), 41-48. 2005

- Bilsborough, S., Mann, N. A review of issues of dietary protein intake in humans. International Journal of Sport Nutrition and Exercise Metabolisim. 16(2), 129-152. 2006

- Protein and aminoacid needs for training and bulking up. Clinical Sports Nutrition. 5th Edition. Sydney Australia. 

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