For quite some time the prevalent expert opinion was that protein intakes beyond the recommended daily allowance of 0.8g/kg body weight would be useless – some experts even claimed that higher protein intakes would be dangerous, as they put extra stress on the kidneys and increase one's risk of low-grade metabolic acidosis and subsequent bone loss.
High protein diets - From villains to heroes in less than a decade
More recently randomized controlled studies and high-quality meta-analyses have refuted both claims. Back in November 2010, Cao & Nilsen (Cao. 2010) published a review which analyzed the outcome of studies that investigated the effect of the purported renal acid load resulting from a high protein intake (above the current Recommended Dietary Allowance of 0.8 g protein/kg body weight) on increased urinary calcium excretion, which they highlight the following points (Cao. 2010):
Higher protein intakes increase bone mineral density and reduce the incidence of fractures.
"Neither whole body calcium balance is, nor are bone status indicators, negatively affected by the increased acid load. Contrary to the supposed detrimental effect of protein, the majority of epidemiological studies have shown that long-term high-protein intake increases bone mineral density and reduces bone fracture incidence" (Cao. 2010)
High protein intakes increase the absorption of calcium and production of IGF-1 and will thus contribute to bone health
"The beneficial effects of protein such as increasing intestinal calcium absorption and circulating IGF-I whereas lowering serum parathyroid hormone sufficiently offset any negative effects of the acid load of protein on bone health" (Cao. 2010)
To hear this message from a researcher may be surprising, but eventually science shows that grains, not meats or other protein sources, contribute the figurative lion's share to the average Westerner's dietary net acid load (Remer. 1995). To say that the high dietary protein load of the Standard American Diet was the driving motor of the osteoporosis epidemic is thus grossly misleading and scientifically unwarranted.
Rather than putting you at risk of osteopenia and kidney disease, diets that are high in protein (and particularly those with high(er) intakes of dairy protein) have been shown …
- to significantly lower systolic and diastolic blood pressure compared to the recommended high carbohydrate diets (Molitor. 2014),
- to powerfully reduce appetite and ad-libitum energy intake and thus to aid weight loss in both strictly energy controlled and ad-libitum (eat as much as you like) scenarios in clinical human studies (Weigle. 2005; Lejeune. 2006),
- to shift the rate of lean mass to fat loss favorable by helping dieters retain lean mass (Piatti. 1994) and increasing fatty acid oxidation (Lejeune. 2006)
- to increase thermogenesis, i.e. the oxidation of (mostly) fat to elevate one's body temperature and ramp up 24h energy expenditure and one's sleeping metabolic rate (Lejeune. 2006),
- to reduce the atherogenic index and thus the heart disease risk of abdominally obese individuals compared to the low(er) protein diet which is still recommended by the American Heart Association (Dumesnil. 2001),
It is thus only logical that more and more experts are recommending an increase in protein intake that goes well-beyond the recommended daily allowance of 0.8g/kg body weight per day.
Threshold intakes and intake frequencies – Both of them can make a difference
There is little doubt that your total protein intake in 24h is probably the most important, it is by no means the only determinant of the health and performance benefits of increased protein intakes. Studies indicate that protein distribution, threshold intakes (per meal) and protein quality cannot be neglected either.
Despite the fact that the importance of protein timing has probably been largely overrated, evidence in favor of beneficial effects of protein distribution ex-ists – and that's not just in the sick or elderly, but also in young, healthy men and women.
Men and women like those who participated in Mamerow et al.'s 2014 seven-day crossover feeding study. In said study, the researchers measured the changes in muscle protein synthesis in response to diets that contained identical amounts of energy, but had different protein distributions between break-fast, lunch, and dinner: Even, with 31.5 ± 1.3, 29.9 ± 1.6, and 32.7 ± 1.6 g protein in each of the meals or SKEWED with 10.7 ± 0.8, 16.0 ± 0.5, and 63.4 ± 3.7 g protein, respectively. To judge the effects on protein synthesis, Mamerow et al. measured the so-called 'fractional protein synthesis', i.e. the protein influx into the muscle.
They found that the 24-h mixed muscle protein fractional synthesis rate was 25% higher in the EVEN (0.075 ± 0.006%/h) vs. the SKEW (0.056 ± 0.006%/h) protein distribution groups (P = 0.003) on day one and after habituation at the end of the 7 day study. A finding that leaves no doubt that "[t]he consumption of a moderate amount of protein at each mea" will, as the scientists say, "[stimulate] 24-h muscle protein synthesis more effectively than skewing protein in-take toward the evening meal" (Mamerow. 2014).
Now many of you will say that they either cannot or do not want to eat higher protein meals for breakfast and / or lunch. With a protein supplement like Thrīv, this would not be necessary, anyway. You just mix the powder with some water and drink it either with breakfast and lunch or simply use it as a nutritious, liquid snack -between breakfast and lunch and / or lunch and dinner. Both would significantly improve the protein distribution and will thus help to augment your 24 h protein synthesis rates.
Improvements in protein distribution are yet not the only important determinant of 24h protein synthesis that can be modulated with protein supplements like Thrīv. They can also help you to achieve a certain threshold level of protein on each of your meals.
While the total amount of protein and its distribution are unquestionably important, the amount of protein and specific amino acids you consume on a per meal basis has been shown to be of similar importance. Bauer et al. (2013), for example, propose in a highly popular paper about the protein requirements of aging men and women that what they call the "per-meal anabolic threshold of dietary protein/amino acid intake" (Bauer. 2013) constitutes a hitherto over-looked, but crucially important determinant of its effect on protein synthesis.
The scientists base this assumption on their observation that a certain protein threshold, i.e. a minimum amount of protein per meal, has to be met by both, older and younger individuals, to kick the protein synthetic machinery into full gear – an observation that is in line with the data in Figure 2, where only the EVEN distribution of protein allowed for a full load of ca. 30g of protein per meal. In the SKEW protein condition, on the other hand, breakfast and lunch had protein contents way below the threshold of ca. 20-30g of high EAA protein sources that has been shown to (a) maximize protein synthesis, (b) promote satiety, and (c) be association with improved body composition and lower amounts of abdominal (Loenneke. 2012; Layman. 2015).
One thing we must not forget is that even the bene-fits most frequent intake of high(er) amounts of protein alone will be limited if the protein sources are of low quality. With protein, both, quantity and quality matter.
Protein quality and amino acid composition – Two true game changers
The "biological value" has been the most common measure to assess the quality of dietary protein for decades. In the past years, however, scientists have turned away from evaluating the quality of certain protein sources based exclusively on the ratio of protein absorption to protein storage in animal studies as it was proposed by Bender et al. in the late 1950s. Rather than that, recent research has been focusing on the physiological effects of certain key-amino acids and bioactive peptides. Molecules like…
- branched-chain amino acids, most prominently leucine, which have been shown to promote muscle protein synthesis, improve blood glucose management and influence fatty oxidation,
- essential amino acids that cannot be produced by the human body and have been shown to have pronounced effects on our bodies' anti-oxidant protection, lipid and glucose metabolism and overall health,
- functional amino acids like taurine, arginine or glutamine which may not be essential, but still vitally important for glucose management, blood pressure control and immune health, and
- bioactive peptides, most prominently from dairy proteins, which have been shown to in-crease satiety, improve blood glucose management, lower blood pressure and much more