Review of 2021

These are the topics that I covered in 2021:


Dietary Guidelines for Americans 2020-2025. The Dietary Guidelines for Americans (DGAs) were published on December 29th, 2020. This post reviewed the newly issued recommendations – what had changed, what had not changed and what were the four over-arching guidelines.

Statins – side effects or nocebo effect? A study published in the NEMJ examined “the nocebo effect.” This is the notion that people experience side effects because they expect to and not because the side effects are genuine. This post includes a letter that Dr David Diamond, Dr Kevin Kip and I wrote to the NEJM highlighting issues with the study and its conclusions.

Men & women & dieting. An article was published from the US DIETFITS study. This study randomised 609 men and women to either a healthy low-carb (HLC) or healthy low-fat (HLF) diet and examined weight loss and other measures over a 12-month period. The study produced interesting findings for low carb and low fat, but it also generated interesting insights into adherence and results for men vs women.


Nuts & cognitive ability. A study was published which claimed that intake of nuts was inversely related to risk of cognitive impairment i.e. the higher the nut intake, the lower the incidence of cognitive impairment. There were so many issues with the study – this post goes through them.

Type 2 diabetes & diet – how low should low carb be? A study was published in the BMJ in mid-January 2021. It was a systematic review and meta-analysis of randomised controlled trials, which examined remission of type 2 diabetes with low and very low carb diets. This study prompts reflection that low carb diets may be just as effective, if not more so, than very low carb diets – taking into account adherence.

The ‘Fat but fit’ debate. A study was published in January 2021, which set out to answer the ‘fat but fit’ debate – if someone has a higher BMI but is active, does the activity make up for the obesity? Can the obese but active person be as healthy as the normal weight inactive person? This post reviews the findings and they were very interesting.

NICE, Vitamin D & Covid-19. The UK National Institute for Care & Health Excellence (NICE) undertook a rapid review of vitamin D for the treatment and prevention of Covid-19. The review was published in December 2020. There was a great deal of evidence in favour of Vitamin D for alleviation/avoidance of bad outcomes with Covid-19. Almost all of it was dismissed by NICE.


Semaglutide & weight loss. There is a class of drug called “incretin mimetics” (which is what semaglutide is), which are used for type 2 diabetes (T2D) as they reduce blood glucose levels. These drugs are now being used/researched for obesity at higher doses than are given for T2D. A study was published in the NEMJ in February 2021. The trial was sponsored, designed, and overseen by the maker of the drug – Novo Nordisk. The results were impressive – so were the side effects and withdrawals from the study.

DIETFITS – who did best? This post built on the January post about low fat vs low carb and men vs women. The study researchers kindly provided access to all data from the study. I used it to ask a different research question – what can we learn from the people who did best (which I defined as a weight loss of 10% or more, of their starting body weight, at 12 months)? This analysis summarises the grams of carb and fat and the percentage of carb and fat as a proportion of total calories that the biggest losers consumed compared to those who gained weight.

How much fruit & veg is optimal? Five-a-day was invented in 1991 at a meeting of the National Cancer Institute (NCI) and the Produce for Better Health Foundation in California. It was a marketing slogan to help companies that benefited from increased fruit and veg consumption. A study was published in March 2021, which sought to investigate the optimal intake of fruit and vegetables for mortality (all-cause, cardiovascular (CVD), cancer and respiratory disease mortality.) The study found that the optimal intake of fruit and vegetables was five portions. What are the odds of that?!

The evidence behind five-a-day. Last week’s note looked at the latest epidemiological study claiming an association between intake of fruit and vegetables and mortality. I promised in that note to share my exchange with Public Health England (PHE) when I asked for the evidence-base for five-a-day. This post shares it.

Do we need to pay people to lose weight? This note was about a ‘new’ scheme that had just been launched in the UK to help people to lose weight and/or maintain a healthy weight. How new was it? What was it based on? Would it work?


Risk factors for women & heart disease. A study was published, which included 28,000 women from the US Women’s Health Study, who were followed-up for 21 years. The goal was to examine the first diagnosis of Coronary Heart Disease (CHD) and to see which risk factors this was most associated with. Some risk factors were huge compared to others. This note explains which.

Meat & disease – again! Yet another epidemiological paper had been published reporting associations between meat intake and different conditions. This post goes through the study in a specific and general way. It tries to arm you with rebuttals for when people try to use nutritional epidemiology to attack your real food, nutrient dense diet.

Anorexia – in memory of Nikki Grahame. This post was written in memory of Nikki Grahame, who lived most of her life with anorexia and tragically died on April 9th, 2021 at the age of 38. The post covers the definition of anorexia from the Diagnostic and Statistical Manual of Mental Disorders and how this fails to capture the essence of the condition. It shares my experiences, of food as a means of control, as a teenager. It covers the incidence of, and prognosis for, anorexia and mortality rates from the condition – the deadliest of all mental health issues. Finally, I address the conundrum of anorexia and the challenge of recovery.

Should Low Carb be High Fat or High Protein? The note title is self explanatory. In his 2008 book “Trick and Treat”, Dr Barry groves included a chapter entitled “Why low-carb diets must be high-fat, not high-protein.” Dr Ted Naiman presented the modern case for high protein – Drs Michael and Mary Eades and Dr Pierre Dukan have presented it previously. Can they all be right?


Transmission of Covid-19 post vaccination. A paper published in the BMJ in October 2020 reported that none of the Covid-19 vaccine trials were designed to test severity of outcome (hospitalisation, intensive care (ICU) or death) or transmission of the virus. A study has been undertaken in Scotland, to investigate a current unknown – whether vaccination can reduce transmission of Covid-19. The study related to healthcare workers and their households in Scotland, during varying lockdown restrictions, and thus it lacked generalisability beyond these circumstances. Notwithstanding this, the study failed to provide convincing evidence that living with a vaccinated person makes the household member less likely to test positive for Covid-19 and it provided no evidence for serious outcomes (hospitalisation being the lowest rung of that ladder) being less likely.

Bad diets, heart disease & deaths. A study was published in April 2021, which reviewed the association between diet and cardiovascular disease (CVD) and deaths (from CVD or any cause). It was different to typical epidemiological studies as it tried to look at dietary patterns rather than single foods (e.g., meat) as usually happens. Both dietary patterns were what I would call junk food diets. The absolute risk differences were tiny. The dietary patterns were so bad that it would have been reasonable to expect far greater association with disease. The biggest finding was how small the impact actually was.

Do we have a weight set point? This week’s note reviews a March 2021 report from a workshop, which set out to examine the concept of a weight set point. This is the idea that whether we gain or lose weight, we tend to gravitate back towards our previous ‘set’ weight. A number of interesting observations emerged from the workshop areas of focus. Environmental and genetic factors impact the weight-reduced state. Weight loss and weight maintenance may be very different physiological states. Strategies may help with one and not the other.

Bariatric surgery 10 years on. A study was published in March 2021, which explored, in depth, patients’ experiences of living with a bariatric surgery procedure for more than a decade. I won’t say much more, as the note explains all. It was really interesting and it made me rethink some of my views about bariatric surgery.

A healthy vegetarian diet. This note was inspired by a query from someone with type 1 diabetes who works with other people with diabetes to help them to control their blood glucose levels. It looks at how easy (or difficult) it is for a vegetarian diet to meet recommended daily allowances (RDAs) for vitamins and minerals. It also examines how much carbohydrate recommended vegetarian diets comprise.


SACN report on lowER carb diets for T2D. In March 2020, SACN, the UK Scientific Advisory Committee for Nutrition, invited submissions for a consultation about lowER carbohydrate diets for adults with type 2 diabetes (T2D). I submitted a response, which is included in this note. The final report was published in June 2021. It concluded that a lowER carb diet can be recommended by clinicians as a short-term option. However, there were five flaws with the consultation document, which have not been addressed and which I go through in this note.

Plant-based diets & Covid-19. A paper was published in June 2021, which led to media headlines that being vegan or pescatarian may reduce the severity of COVID-19. There wasn’t even a vegan diet in the study. This paper was misleading at best and disingenuous at worst. I had a rapid response published in the journal.

Cholesterol & mortality – world graphs. This post shares an update to a 2010 post, which examined deaths from heart disease and all causes for men and women for 192 countries against country mean cholesterol levels. All charts were inverse. The higher the cholesterol levels, the lower the deaths.

Rebutting the cholesterol hypothesis. This note suggests a rapid rebuttal to the cholesterol hypothesis. To get there, it goes through the history of how the cholesterol hypothesis developed and mutated over time. From Russian pathologists to Dr Ancel Keys and to the current focus on saturated fat and Low-Density-Lipoprotein cholesterol (LDL-C).


Chocolate for breakfast may help fat burning. I love chocolate but this study was so bad, it was difficult to know where to start. It did not find what it claimed, but it was interesting nonetheless.

Stopping statins. A study was published in JAMA Open Network, which generated the headline ‘stopping statins linked to death and cardiovascular events in the elderly.’ The claims were impressive, but they did not withstand scrutiny.

Plant-based ‘meat’ vs grass-fed meat. A paper was published in Nature Scientific Reports in July 2021. It used an analytical profiling technique (metabolomics) to compare plant-based ‘meat’ and grass-fed meat for thousands of nutrients and outputs of the metabolic process (metabolites). The authors concluded that “a plant burger is not really a beef burger.” No kidding!

The National Food Strategy: The Plan. “The (England) National Food Strategy: The Plan” was published in July 2021. This note looks at parts of the plan of most interest to real foodies: breaking the junk food cycle; meat; and plant vs animal protein, along with the strategic objectives, recommendations and limiting assumptions in the report.


What should we eat? It’s only fair to follow a critique of the national food strategy with a statement of what I would recommend. This is the most succinct post I’ve ever written on what is food? What is weight loss? What should we eat and why?

Vasectomies: testing & clearance. A bit of a departure from the normal subject areas, but I had the opportunity to co-author a paper, which was published in BMJ Sexual & Reproductive Health about different testing strategies post vasectomy. The paper asked and answered important questions: Q1) Does postal testing increase compliance? Q2) Following compliance how do clinical outcomes (early and late failures) compare? Q3) What significance does this have for clinical practice? This paper could elicit procedural change in the vasectomy world.

Meat & heart disease. Another attack on meat was published in July 2021. This one concluded that 50g/day more UNprocessed meat was (slightly) associated with heart disease (9% relative risk), processed meat was a bit more associated (18% relative risk), and poultry wasn’t associated with heart disease. The paper was a systematic review and meta-analysis, but of population studies. It thus suffered from the usual limitations of epidemiology: association not causation; relative not absolute risk; and the healthy person confounder.

Keto diet under attack. A narrative review was published about ketogenic diets by authors with plant-based diet conflicts. The paper went through several conditions, from diabetes to kidney disease, reviewing the evidence for benefit or harm from ketogenic diets. The authors struggled to be positive about keto diets, so I looked at where their criticisms were fair and unfair.

Fast’ & ‘slow’ carbs. A study was published claiming that higher glycemic index (GI) carbs don’t cause obesity. It reviewed observational studies and randomised controlled trials. The claims that high vs low GI (fast vs slow carbs) had been studied did not hold up, let alone the findings.


Aspirin & cancer survival. This post generated much interest. It examined a very large systematic review and meta-analysis of 118 studies, which reviewed aspirin for cancer post diagnosis. Some of the findings and numbers on possible life extension among patients taking aspirin were impressive.

Inclisiran. A PCSK9 inhibitor has been approved for use in the UK (not in the US at the time of this post). This was despite there being no evidence (at the time of this post) for any cardiovascular benefit from taking inclisiran.

The Carbohydrate Insulin Model of obesity. This note reviewed a perspective paper which had just been published on the carbohydrate insulin model (CIM) of obesity. The paper was an excellent summary of the model and our thinking about obesity generally.

Energy compensation & adiposity. This novel and interesting paper showed that just as when we eat less, the body can do less, so if we try to do more, the body will try to do less. There are thus a number of ways in which do more (and also eat less) conspire against us so that the body does less rather than giving up body fat. The additional (cruel) finding of this study was that the compensation was larger in those with higher BMIs.


The Zoe app, Covid-19 & supplements. This paper used data from 445,850 subscribers to the Zoe app to see if there was an association between taking certain supplements and being less likely to test positive for SARS-CoV-2 (PCR test). It found that there was a lower chance of testing positive for SARS-CoV-2 among people who supplemented with multivitamins, vitamin D, probiotics and/or omega-3 fatty acids. Vitamin C, zinc and garlic made no significant difference. There were striking differences between men and women and different countries, however, and not all could be explained.

Towards better dietary guidelines. A special issue of Nutrients was published comprising three papers related to the Dietary Guidelines for Americans (DGAs): one on saturated fat; one on low carb diets; and the third on salt/sodium intake. Much evidence was presented in these papers, which had not been considered by the Dietary Guidelines Advisory Committee, to the detriment of American and world health.

Weight loss vs fitness for health risks. This post reviewed a paper, which examined the benefits of increasing fitness and physical activity vs weight loss for reducing health risks. It focused on deaths and cardiovascular disease. It presented compelling evidence for the benefits of exercise. The case for exercise being better than weight loss was less compelling.

Australian women – carbs & fat. A study of approximately 10,000 middle-aged Australian women examined the association between carbohydrate and saturated fat intake with cardiovascular disease (CVD) and deaths from any cause (mortality) over a 15 year period. It found no association between carbohydrate intake and mortality or between saturated fat intake and CVD or mortality. This study suffers from the usual limitations of epidemiology, but it was interesting that it had contrary findings to many other nutritional population studies.


Food Compass – Part 1. This was the first of a two part examination of a new nutrient profiling system (NPS) – called Food Compass – developed by Professor Dariush Mozaffarian and colleagues. Nutrient profiling systems aim to differentiate between the healthiness of different foods and food groups. There are more than 100 such systems already. The team behind Food Compass argued that current NPSs suffer from deficiencies, which Food Compass aimed to overcome.

Food Compass – Part 2. The second part of this two-part note covers more individual foods. As a teaser, examples of foods scoring 100 (out of 100) were Uncle Sam cereal; soybeans, dry, cooked, fat not added in cooking; and raw halibut. Examples of foods scoring 1 (out of 100) were white rice; mixed pickles; canned ham/luncheon meat; and wonton soup.

The Clot Thickens. This was a review of Dr Malcolm Kendrick’s new book with the clotting theory of heart disease. The book is structured with an introduction and two parts. The introduction set out the diet heart hypothesis and why it is wrong. Part 1 of the book set out the clotting hypothesis and its origins and inspirations. Part 2 covers what we can do to reduce the risk of heart disease in the context of the clotting hypothesis (and potential life expectancy gained from reducing different risks).

COVID-19 Anxiety Syndrome Scale. This week’s note looks at the work of Professors Marcantonio Spada and Ana Nikčević. They, and later joined by colleagues, developed and validated a tool, which they named the COVID-19 Anxiety Syndrome Scale (C-19ASS). The scale has been validated against an established personality profiling tool – the Big Five Inventory – and against peer anxiety models developed in 2020. It has turned out to be a valid tool for measuring the level of anxiety related to COVID-19. It was also found to be uniquely helpful for identifying attentional bias (where one’s attention is most focused).

Keto diets & kidney stones. This week’s study produced the headline finding that the estimated incidence of kidney stones in patients on a ketogenic diet is 5.9/5.6% vs. 0.3% per year in men and 0.25% per year in women in the general population. However, the 36 studies were predominantly (29/36) of children with epilepsy, and none were about healthy children or adults. This study was not about keto diets in healthy people or even people with metabolic syndrome and thus can largely be ignored.


Global meat trade & health. A study recently claimed that 5,000 people die each year because of trade of red and processed meat. The study was a modelling exercise and thus whatever is assumed will be found by the model. The paper noted that trade in meat can balance the availability of nutrition, but no further recognition was given to the positive health benefits of meat. Only downsides were assumed to count. As with other attacks on meat, the notion that an ancient food is responsible for the most modern illnesses (cancer, type 2 diabetes and heart disease) makes no sense.

Efficacy, NNT & safety. For a drug intended to prevent disease, an efficacy figure of, say, 90% is usually thought to mean that, if 100 people take the drug, 90 people won’t get the disease. It doesn’t mean this. This note goes through what efficacy does mean, what the number needed to treat is (NNT) and how intervention safety should be factored into decision making.

Christmas & weight gain. This note looks at three academic studies (UK, US and Europe), which examined weight gain over the Christmas period. The rest of the note shares my top five tips for avoiding weight gain during this and any other period of celebration.

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