Managing Human Hunger Appetites

Studies over a 30 year period have discovered new facts about human nutrition, that changes how we understand appetite, explains the obesity epidemic and suggests a way to solve that. Here are the main points of their theory.

Appetite balancing is common across the animal kingdom, including slime molds, cockroaches, spiders, cats, dogs, mink and non-human primates. Some species turn out to have two appetites. Others have five appetites for specific nutritional requirements: three for the main macro-nutrients (protein, carbohydrates and fat) and two for specific micro-nutrients (sodium and calcium).

If a species were to have a separate appetite for each necessary nutrient, they would need complex biological  systems. Species have evolved to focus on the nutrients that are needed in very specific quantities. For other things, natural diets were rich enough for them to automatically get enough of the other nutrients needed. In a food environment that is poor in one of the essential nutrients, individuals will eat more of other items in order to keep up the calorie requirements.

Humans are among the five appetite species. People typically need 15% to 20% of daily calories from protein. It turns out that humans are living in a protein dilute, energy-rich environment. Between 1961 and 2000, the proportion of protein in an average US diet fell from 14% to 12.5%, with the balance made up fats and carbohydrates.That shift was the only way people could maintain target protein consumption was to increase total calories intake by 13% - more than enough to create an obesity epidemic.

Experiments have shown that most of the extra calories eaten by those on a low protein diet came from savoury snacks, especially those tasting of umami, the signature flavour of protein. The protein-deprived were craving things that tasted of protein, even though composed of carbohydrates.

Ultra-processed foods are designed to be irresistable, and tend to be low in protein (expensive) and high in cheap carbs and fats. Such foods include pizzas, crisps, breakfast cereals, sweets, bread, cakes, mayonnaise, ketchup and ice cream, items which make up more than half of a typical US and UK diet - with some people eating these almost to the exclusion of everything else.

Our appetite for protein is stronger than our ability to limit carb and fat intake, so when protein is scarce, our appetite for it overwhelms the mechanisms that normally tell us to stop eating fats and carbs. Ultra-processed foods also contain very little fibre, which is filling and puts a brake on our intake.

How to manage your appetites

1. Calculate your protein target by looking up the daily energy requirement for your age, sex and level of activity. (This is can be done with the Harris Benedict equation calculator, available on many websites).
2. Work our the proportion that should come from protein by multiplying that figure by 0.15 (to give the 15% of energy from protein). Depending on age, you might need to use the multiplier of 0.18 (for 18% needed by 18 to 30 year olds), 0.17 (for the 17% needed by those in their 30s, or 0.2 (for those over 65 who need 65%).
3. Divide the resulting number by 4 to get the number of grams of protein a day you should eat. ( gram of protein contains 4 kilocaolories of energy.)
4. Then work out how to obtain that protein from protein-rich foods such as meat, fish, eggs, dairy, pulses, nuts and seeds. The protein content is often listed on food labels, or available online.
5. If you eat this amount of protein, it will satisfy your protein appetite and automatically ensure you don't overeat carbs and fats you won't need to track these at all).
6. Make sure you supplement the high-protein foods with mostly wholefoods, mainly plant-based, which will also supply your fibre needs.
7. Most importantly, avoid ultra-processed foods by keeping them out of the house.

Source: article: In perfect balance by David Raubenheimer and Stephen Simpson, New Scientist 23 May 2020.

Adolescent and Lifetime Offenders

Long-term research into male anti-social behaviour indicates that it is concentrated in adolescence, with fewer than 10% of males committing more than 50% of crimes. The offenders fall into two groups in adulthood, lifetime offenders and adolescent delinquents. A third group never offend.

Life-course persistent offenders (LCPO). Show extreme/violent anti-social behaviour from early childhood and on into adulthood. Brain scans show that LCPO individuals have less grey matter in some regions of the cortex, most of which are linked to anti-social behaviour (goal-directed behaviour, regulation of emotions and motivation). Possible causes are: (a) born with brain structure abnormalities, (b) bad childhoods or (c) both of these.

Most people with a low polygenic score for educational achievement have a lifelong struggle with self-control.They also tend to be late talking, don't use language very well, have difficulty learning to read, trouble concentrating and controlling thoughts, and struggle to remember facts and figures. This means that they find school frustrating and humiliating, and leave as soon as they can. A lack of qualifications leads to difficulty finding a job, and turning to a life of crime (and if good at it, brings self-esteem). LCPO are still locked up to keep the public safe.

Adolescent limited delinquents (ALD). Show a similar level of anti-social behaviour at around 18 but grow out of it. Deprivation, abuse and neglect allow vulnerability grow into anti-social/criminal behaviour. Many adolescents feel the need to prove themselves as adults and commit risky crimes, but once entered into adulthood, this lifestyle loses its appeal.

It is easy to walk away from offending if you have avoided having a criminal record. UK policy therefore tries to divert away from courts and jails, using approaches that aim to contain and change their behaviour without bringing formal charges.

Not-offending (NO). These individuals never commit anti-social behaviour. They simply don't want to break the law and adolescent culture no longer sees them as outcasts (the 'goody-goody' ones).

What we need to do.

• Develop treatments and rehabilitation protocols rather than invest in new prisons. 
• Effective prevention programmes need to start in early childhood. 

Source: Crime and punishment article in New Scientist by Terri Moffitt, King's College, London (July 2020)

Covid-19 Management Strategies

The most important fact is that this is a new virus for humans and we are still learning about how it infects, spreads and affects sufferers, and how best societies can deal with the problems.

1. The typical incubation period is thought to be 5 or 6 days. Since at this point it can be spread before symptoms occur (and in some cases sufferers show no symptoms) reducing spread requires reducing social interactions.
2. Herd immunity is a poor strategy, as post-infection immunity is not proven. It leaves lasting ill effects for many sufferers, both physical and mental.
3. Lockdown timing is crucial. Best to do this early and lower the R number - how many people an infected person can infect before showing symptoms.
4. Lockdowns vary in impact on different societies. Worst in densely populated low and middle income countries, with low quality housing and loss of income.
5. Lockdowns most effective early, and once levels are minimal, localised lockdowns at infection hotspots. (Pakistan is trying 2 weeks locked down followed by 2 weeks fewer restrictions - it remains to be seen if this is effective.)
6. Enforce border controls early. People working abroad panic and want to return home. Such mass migrations are difficult to screen effectively. They are hard to implement and people find ways around them. Putting people into enforced quarantine ties up a lot of resources, money that is better spent elsewhere.
7. Block the right travel routes. Blocking travel from China to the US did not help, as the early spread into the USA was from Europe.
8. Government messaging needs to be clear, concise and follow best practice. Mixed messaging causes uncertainty and less compliance. Certain national leaders have made decisions that have worsened their country's infection rate.
9. Mask wearing. There is a lack of good trials that prove the most effective slowdown of infections. Current scientific views are that wearing a mask reduces the risk of you spreading the infection to others, so it is important that as many people as possible do so. It is thought that wearing a mask might also help people to remember to keep other members of the public at the recommended distance.

Sources: various.

Cancer

We are all familiar with the various types of cancer which occur in various parts of our body, breast cancer, pancreatic cancer, skin cancer and so on.

However some people have vague and non-specific symptoms, and only when they have scans are cancerous growths are discovered and then confirmed by biopsy.

Referred to as CUP cancers (cancinoma of unknown primary), these tumours have little relationship to the organ or tissue where the growth is found, and a primary tumour is not found. World-wide some 3% to 5% of tumours world-wide fall into this category.

Among researchers there is a growing feeling that CUP may be a specific type of cancer, rather than a metastasis from a primary.

Work is ongoing to identify metastatic tumour driver genetic mutations. If the tumour shows a specific mutation that is a feature of a known organ or tissue cancer, then using the current treatment for that cancer might be effective. For example, a specific mutation in the BRAC1 or 2 gene (one of the causes of breast cancer) might be causing growths elsewhere, which might respond to the PARP inhibitor. For CUP sufferers it will mean personalising therapy for the best outcome, rather than focusing on the organ or tissue in which the cancer occurs.

Source: feature in New Scientist, 11 July 2020