Facts on the Need for More Protein by Joan Kent, PhD

Some years ago (1997 to be exact), the American Journal of Clinical Nutrition featured an article stating that women’s protein needs had been underestimated up until then.

In the same issue, a different article discussed the higher rate of serotonin turnover in women’s brains versus that of men. Serotonin is made from the amino acid tryptophan. Amino acids make up proteins. So women need extra protein for that reason.

The same year, Smith et al. published a study in the Lancet describing the return of depression in susceptible women after rapid depletion of tryptophan. So women need protein for that reason.

A long-held theory of mine is that people who think dietary protein isn’t important don’t recognize the need for “brain protein.” That’s true, but it turns out protein is now being declared important for other reasons, as well – weight loss, satiety, lean body mass, athletic performance, aging and others.  I’ve been stressing all of those reasons for many years.

• In 2012, adult protein requirements were assessed at 10% higher than previous assessments – for both men and women and all age groups (Millward, 2012).
• A 12-week weight loss study in overweight adults showed that higher protein intake promoted better retention of lean body mass in trunk and legs (Tang et al., 2013).
• Maintaining adequate protein intake with aging may help preserve muscle mass and strength in adult men and women. The type of dietary protein may affect muscle mass and strength, too: animal protein promoted higher lean leg mass, while plant protein did not (Sahni et al., 2015).
• Older women in the higher protein group (1.1g/kg/day vs. 0.8g/kg/day) had lower body mass index and lower fat-to-lean ratio than those in the lower protein group. The lower protein diet also resulted in impaired strength in upper and lower extremities (Gregorio et al., 2014).
• Evenly distributed protein intake – approximately 30 g of protein per meal – stimulated muscle protein synthesis more effectively than the typical pattern of skewing protein toward the evening meal, with a breakfast higher in carbs and lower in protein (Mamerow et al., 2014).
• A recent seminar by the American Council on Exercise on protein’s role in weight loss and satiety recommended protein intake of 30 grams per meal, 3 times a day.
• Two studies indicated a need for increased protein intake to ensure that “non-essential amino acids” would be adequate for optimal growth, reproduction and resistance to metabolic and infectious diseases (Hou et al, 2015; Wu et al, 2013). Essential amino acids are not synthesized by the body and must be consumed in food. Non-essential amino acids are generally assumed to be adequately synthesized by the body for maximal growth and health. These two studies by Hou et al. and Wu et al. counter that assumption and recommend increased dietary protein.
• Female football players have protein needs similar to those of male players (Maughan and Shirreff, 2007).
• Women strength athletes may require more protein than either endurance-trained or sedentary women. Recommendations call for less emphasis on carb intake and more emphasis on quality protein and fat consumption to enhance training adaptations and general health (Volek et al, 2006). Compared to men, women seem to rely less on glycogen during exercise and be less responsive to carb-mediated glycogen synthesis during recovery.
• Minimum protein intakes should be approximately 25% of total calorie intake (Fulgoni 2008). Many adult men and women get only 15% of their energy intake from protein.
• In a 12-week study, a daily high-protein (35g) breakfast prevented gains in body fat. A “normal” protein breakfast did not. The high-protein breakfast reduced hunger and led to voluntary reductions of about 400 calories per day (Leidy, et al 2015).

Stewart Phillips, PhD, FACSM, FACN, and professor at McMaster University critiques the long-touted RDA of 0.8 g of protein/kg/day: “Nothing about that level should be recommended, and you’re allowed to eat much more. In fact, for older persons and athletes (my italics), there are benefits to consuming protein at levels above the RDA.”

Indoor cycling instructors are athletes — and regular cycling participants may be, as well. Whichever way you train, if you work out hard and often, be careful not to underestimate your protein needs.

Don’t put off addressing your nutrition! If you’d like help with that, I’m dedicated to helping you. Just visit LastResortNutrition.com and grab your free Empowered Eating Consult. Find out how easy it is to make small tweaks that produce big results!

 

Brought to you by Dr. Joan Kent, best-selling author of Stronger Than Sugar.