You are not entitled to your opinion

June 29, 2012 § Leave a comment

“You are not entitled to your opinion. You are entitled to your informed opinion. No one is entitled to be ignorant.”

Harlan Ellison

Science is a way of thinking

June 21, 2012 § Leave a comment

Science is a way of thinking much more than it is a body of knowledge.
Carl Sagan

LinkedIn Advice to Users

June 8, 2012 § Leave a comment

Following the news of the Six Million LinkedIn Password Leaked LinkedIn have issued a statement about the leak with the following advice:

  • Make sure you update your password on LinkedIn (and any site that you visit on the Web) at least once every few months.
  • Do not use the same password for multiple sites or accounts.
  • Create a strong password for your account, one that includes letters, numbers, and other characters.
  • Watch out for phishing emails and spam emails requesting personal or sensitive information.

Six Million LinkedIn Passwords ‘Leaked’

June 6, 2012 § 2 Comments

It appears that the security of more than six million LinkedIn accounts has been compromised. It is recommended that LinkedIn users change their passwords and the passwords of other sites using the same password.

The passwords have been posted on the Internet in encrypted form but it would seem that some have already been cracked.

The following advice is taken from the BBC report breaking the news.

What to do

Security experts have advised users to change their passwords on LinkedIn. Here’s how:

  1. Visit www.linkedin.com, and log-in with your details
  2. Once logged-in, hover over your name in the top right-hand corner of the screen, and select ‘Settings’ from the menu
  3. You may be asked to log-in again at this point
  4. On the next screen, click the ‘Account’ button which is near the bottom of the page
  5. Under the ‘Email & Password’ heading, you will find a link to change your password

If you use the same password on other sites, be sure to change those too.

New website: Crafts by Hazel

May 14, 2012 § Leave a comment

Crafts by Hazel homepage

Crafts by Hazel homepage viewed on a Desktop PC

A new website has been launched for Hazel Browne to showcase her Arts & Crafts work.

It features an image carousel to rotate images to display examples of Hazel’s work on the homepage

This is a responsive website meaning that it adjusts to the device it is displayed on.

Crafts by Hazel mobile image

Crafts by Hazel homepage on a mobile

The two images here show the same homepage as it might appear on a desktop PC (above) or a mobile phone (right).

Please visit Crafts by Hazel to see more.

The Truth about Fat

March 24, 2012 § Leave a comment

Surgeon Gabriel Weston claims that we are in the middle of a fat epidemic. In this week’s Horizon documentary she seeks to explain a “mystery”, why she asks when we are all surrounded with ample food do some people pile on the pounds while others do not?

Weston’s documentary makes an appropriate companion piece to last week’s The Truth about Exercise. The focus this week is on appetite and individual differences. Weston tells us that there is a hunger hormone (Ghrelin) and a fullness hormone (PYY). Dr Carel Le Roux says that the gut talks to the brain and influences how hungry or full we feel.

Using a functional MRI scan Weston’s brain is shown to be normal, with limited activation in response to calorie-rich food. By comparison a scan of an obese person’s brain reveals considerable activation in areas of the brain associated with “reward-centres”, addiction and emotional responses to food. Psychiatrist Dr Samantha Scholtz says that gastric bypass surgery can change the way the brain responds to food. 21 stone Marylin Walsh underwent a stomach bypass operation at Dr Le Roux’s hospital; within weeks she had lost four stones. More interestingly she reports that she no longer desires sweet or fatty foods. Weston is shown before and after brain scans of an obese person who had a stomach bypass and while the before image demonstrated great activity in response to high calorie foods, the post-operation scan shows minimal activity just like Weston’s own scan.

Discussion

The Truth about Fat is an interesting documentary but while I found Gabriel Weston’s narrative compelling I kept wondering if there were alternative explanations that were not offered. I felt that time given over to dissections of pigs to show us visceral fat might have been better dedicated to providing stronger evidence to support the theories advanced.

At the start of the programme  Weston explains that the human brain evolved at a time when food was scarce and therefore is attuned to storing energy, however in today’s world with plentiful food available 24/7, behaviour that was once useful to human survival is maladjusted to modern life. An interesting theory, but why I wondered has the fat epidemic that Weston talks about only taken hold (outside of the US) in the last 2o years when for most of the 20th century food has been cheaper and more plentiful than any other time in our history. While I find Weston’s explanations quite persuasive I felt she need to go a little further to make her case completely convincing.

Another example is the former shot putter who tells us that despite being very motivated he found it impossible to increase his weight beyond a certain point. This is an interesting change of tack from the usual case studies of people trying to lose weight; however this was only one person and therefor it is impossible to say whether this individual is a one-off or representative of the wider population.

3500 kcal equals 1 pound of body weight: fact or myth?

March 18, 2012 § Leave a comment

In the article ‘What’s a few billion neurons between friends?‘ I expressed surprise that the figure of 100 billion neurons in the human brain was often repeated despite no one seeming to know where the figure came from. It reminded me of a claim I heard regarding the usual answer to a common dieting question: ‘how many calories do I need to burn to lose 1lb of weight’. There are different variations to this question but the answer is almost invariably the same – 3,500 calories.

By chance I caught the end of a radio interview with a lady who was questioning the provenance of this figure, which like the number of neurons in the brain, had gained general acceptance. I didn’t hear the name of the interviewee and was unable to follow up the claim that the 3,500 calories figure is a myth, but I now believe the person involved was Zoë Harcombe.

In her article ‘1 lb does not equal 3,500 calories‘ Zoe says that she asked several organisations (the National Health Service (NHS); the National Institute for Clinical Excellence (NICE); the Department of Health; the National Obesity Forum; the Association for the Study of Obesity; the British Dietetic Association and Dieticians in Obesity Management) where the 3,500 figure came from but none of them were able to provide a satisfactory answer. This is an interesting line of investigation which I will comment on later but first I want to focus on her claim that ‘you will struggle to find anyone demonstrate the precise calculation behind this’.

True, I did struggle at first but only because attempts to Google the answer only brought up page after page of links to forums, blogs and articles asking how many calories are in a pound of weight. However, searching more academic sources I found articles referencing the work of Max Wishnofsky. Wishnofsky’s 1958 article ‘Caloric Equivalents of Gained or Lost Weight‘ provides the following explanation:

“… the average fat content of human adipose tissue taken from various parts of the bodies of well-nounished subjects is 87 per cent. One pound (454 g) of human adipose tissue, therefore, contains 395 g of fat. The caloric value of one g of animal fat is 9.5 ; consequently, the caloric equivalent of one pound of human adipose tissue may be considered to be about 3,750 cal.”

My research also produced several references to Dr Gilbert B Forbes. Forbes observed that body weight changes involves both body fat and fat-free body mass and devised a formula to reflect this. As Forbes states in ‘Body fat content influences the body composition response to nutrition and exercise‘:

“In most situations involving a significant change in body weight, both fat-free body mass (FFM) and body fat participate, but the relative contribution of FFM and fat to the total weight change is influenced by the initial body fat content.”

Hall revisited Forbes’s work and devised a new formula. This formula produces results that ‘… compared favorably with data from human under-feeding and over-feeding experiments and accounted for previously unexplained trends in the data’. In another journal article Hall asks the question “under what conditions is it appropriate to use this rule of thumb and what are the factors that determine the cumulative energy deficit required per unit weight loss?” The rule of thumb Hall refers to is the need to create a calorie deficit of 3,500 calories in order to lose one pound of weight. Hall comes to the conclusion:

“The rule of thumb approximately matches the predicted energy density of lost weight in obese subjects with an initial body fat above 30 kg but overestimates the cumulative energy deficit required per unit weight loss for people with lower initial body fat.”

Returning to the point raised by Zoe Harcombe, several organisations she questioned were unable to say where the 3,500 calorie figure came from. It is a figure repeated by “government literature, in just about every diet book, in private health booklets and all over the internet’. Zoe’s investigations show that too often received wisdom is accepted without looking deeper and checking sources. Since my first draft of this article I have looked deeper and after checking Zoe’s sources I realise that not only did she know about Wishnofsky’s work she even referenced his 1958 article in her book The Obesity Epidemic.

Other than the point about the need for trusted organisations to be more careful about the provenance of the information repeated to the public, an interesting point to arise from this investigation is that the truth about how many calories are in a pound of body weight is more complex than is commonly recognized.

My investigations show that 3,500 figure is not wrong per se and is certainly not a myth, but rather it is a rule of thumb that cannot be applied blindly. So do 3,500 kcal equals 1 pound of body weight? The answer is ‘sometimes’.