🤸‍♀️ How much protein to retain muscles if training and cutting calories?

People often go on calorie restriction to lose fat mass, while performing resistance training to retain fat free mass (a measure that includes muscles, bones, organs, connective tissues and water). Fat free mas is often used as a proxy for muscle mass in research.

Recent research reviewed 39 studies to understand what are the protein requirements for individuals in these circumstances.

The findings are:

• More protein equals better retention of fat free mass. In scientific term, a linear dose-response relationship was found between protein intake and favourable fat-free mass changes.

• Optimal protein intakes for minimising losses in fat free mass were identified as 1.9 g/kg of body weight per day or 2.5 g/kg of fat-free mass per day.

• Protein intakes above these thresholds (up to 3.2 g/kg of body weight per day) were associated with significant fat free mass gain, but the beneficial effect diminished the grater the protein intake.

• The greatest benefits were seen in leaner individuals and for dietary interventions lasting longer than 4 weeks

🥊 Punchline

Increasing protein intake can be beneficial in retaining fat free mass (and muscle mass) when in people doing resistance training under calorie restriction, especially in lean individuals. However, this approach has to be balanced within a broader nutritional strategy to maintain energy availability.

💪 Fatty muscles raise the risk of serious heart disease

Fat infiltration in muscle reflects muscle quality and is associated with inflammation, a key determinant in cardiovascular and metabolic disease.

However, little is known about this type of body fat in humans, and its impact on health.

A novel study looked at the effects of fatty muscles on heart disease, small blood vessels and 'microcirculation' of the heart.

People with pockets of fat hidden inside their muscles are at a higher risk of dying or being hospitalized from a heart attack or heart failure, regardless of their BMI.

Higher amounts of fat stored in the muscles are more likely to increase inflammation and alter sugar metabolism leading to insulin resistance and metabolic syndrome. All of which, could damage the tiny blood vessels that serve the heart.

For every 1% increase in fatty muscle fraction, there was a 2% increase in the risk of dysfunction tot he heart circulation and a 7% increased risk of future serious heart disease, regardless of other known risk factors and body mass index. Fat stored under the skin (subcutaneous fat) did not increase the risk.

This is important because it assessed the effect of ‘organ fat’ on cardiovascular disease risk in a population of predominantly older females with high rate of obesity.

These findings raise the question that existing measures (e.g. BMI) are not adequate to evaluate the risk of heart disease accurately for all people, especially in women where high BMI may reflect more 'benign' types of fat.

🥊 Punchline

People who had high levels of intermuscular fat and evidence of dysfunctional coronary circulation were at an especially high risk of death, heart attack and heart failure. In contrast, people with higher amounts of lean muscle had a lower risk.

😳 Does diet play a role in acne?

Acne affects 80 - 95% of teenagers and adults in the UK, with around 50% of the over 30s continuing to experience symptoms.

Research from 2002 that is still relevant today investigated the role of diet in acne development.

Researchers investigated the prevalence of acne in two non-westernised populations; the Kitavan Islanders of Papua New Guinea and the Aché population in Paraguay.

Both populations followed a diet consisting mainly of home-grown produce and wild, foraged foods, as well as wild game and the meat of some farmed animals for the Aché. These diet habits still remain virtually uninfluenced by Western foods.

There are no highly sweetened or processed products and food is preserved using time-honoured, traditional methods. Intake of alcohol, sugar, tea, coffee, dairy, wheat and salt, for example, is nil or negligible.

No acne was observed in any participant during the day period.

Other populations, such as the inhabitants of Okinawa (Japan) and the Zulu (South Africa), who moved from their rural villages to the cities saw their incidence of acne going up dramatically. This was associated with the increasing availability of mass-produced ready-made products.

The effects of mass-produced ready-made products seems to be mediated through our gut health, but very little is known about the mechanisms.

🥊 Punchline

Adoption of a westernised diet and culture correlated with greater risk of acne development.