"Firm facts to shift the fat"...and the trigger was pulled for Rachel.

After she received several rapid-fire text messages in quick succession from scientific colleagues – asking if she was watching the national news, she quickly turned on the TV and wished she hadn’t.
 
What followed was several minutes of blood pressure-inducing half-truths, misleading statements, mixed in with some utter nonsense.
 
Lo and behold, it was Michael Mosley (described as a health guru!) promoting his latest diet book: The Fast 800 Keto.
 
In the introduction to this news piece, we’re told: ‘it’s time for some firm facts to shift the fat’. Now if you want firm facts, someone who is directly profiting from book sales, is not your go-to person – they are hardly impartial.
 
Check out Issue 24 for our take on diet books. Basically, anyone profiting from exaggerated, one-sided claims in diet books should be treated with a healthy dose of scepticism.
 
It’s not our intention to beat up on keto or fasting, but instead call out overly zealous claims that lack evidence. Unbalanced views can lead to lots of confusion.
 
So, what really got under her skin?
 
Point 1: Does following a keto diet cause ketoacidosis?

When asked how keto works, Mosley responds: ‘it works by putting your body into a state of ketoacidosis’. Well, if this were the case – most keto junkies would be very ill, if not dead.

Ketoacidosis is a life-threatening condition where uncontrolled production of ketones results in metabolic acidosis. This is most often seen among people with poorly managed type 1 diabetes. Here, because of a lack of insulin, the body can’t use glucose as a fuel and so relies on the breakdown of fat.

This rapid breakdown of fat produces ketones, but at a rate that can’t be processed by the body, and so ketones build up in the blood causing it to become acidic – hence, the term ketoacidosis. Symptoms include tiredness, dizziness, nausea, extreme thirst, and breathlessness.

What Mosley was in fact referring to was ketosis. This is where ketone levels in the blood and urine rise as a result of low carbohydrate availability – the body starts using more fat as a fuel source and ketones are produced, but at levels that the body can process. In ketosis levels rise to around 0.5 to 3 mmol/L; levels seen in ketoacidosis are up to 10 times higher.
 
So now we have that cleared up – what’s all the fuss about ketosis?

There are claims that ketosis reduces appetite, so we eat less.

An elegant study published last year by Kevin Hall’s group sheds some light on this claim. In a randomised crossover study, 20 participants were provided with an ad libitum high-fat keto diet or low-fat plant-based diet under very controlled conditions (i.e., they were in-patients) over two weeks. Both diets contained minimally processed foods – this point is important.

The researchers measured ad libitum intakes over the two weeks. They specifically examined intakes during the second week when ketones were likely to be higher and thus, more likely to elicit a greater effect.

Over the two week period participants consumed statistically significantly less energy (689 kcal/d or 2880 kJ/d) following the plant-based diet compared to keto.

When looking at week 2 only, the difference between the two groups was attenuated to 544 kcal/d (2274 kJ/d). Nutritional ketosis (blood levels > 0.5 mmol/L) occurred after a few days and was highest during the second week averaging 1.8 mmol/L. It’s possible that these higher circulating levels of ketones during week 2 reduced appetite. But that said, participants still consumed significantly more calories during the high-fat keto period compared to when they ate the low-fat plant-based diet.

So, at best we can speculate that as ketones rise, they can suppress appetite, but the effect on calorie intake is less than we see when consuming other unprocessed low fat, plant-based diets.
 
Point 2: High fat dairy is a 'good' fat

Mosley rightly points out that the type of fat in our diet is important – perhaps more important than the total amount of fat. He also sings the praises of fatty fish - so both of these points get a tick from us

But, Mosley also seems to be a fan of high fat dairy.

While some research suggests certain higher fat dairy products such as yoghurt and cheese don’t appear to have the same deleterious effects as butter, the research in this area is far from a slam dunk.

Check out Issue 12 for a more in-depth chat on this topic. In this issue we highlighted a study examining three large cohorts of over 222,000 participants, which showed that isocaloric replacement of 5% of dairy fat with polyunsaturated or vegetable fat was associated with a 24% and 10% reduction in cardiovascular disease risk, respectively.
 
Point 3: Exercise is not useful for body weight regulation

Mosley contradicts himself here. Firstly, he comments that exercise is good for lots of things such as the brain and mood, but stresses exercise is not good for weight loss.

At the end of the interview when asked ‘what is the one thing people could do right now to improve their health’ – he suggests people go for a brisk walk (around 100 steps per minute), and in a fasted state before breakfast so you burn more fat. Confused...?

We agree that compared to exercise, diet has a greater impact on weight loss, but there is a wealth of information on the importance of exercise for weight maintenance. There’s also heaps of other reasons to be physically active.

But what about exercising in a fasted state. This does cause a spike in the amount of fat oxidised, but over a 24-hour period the effect is minimal. A meta-analysis of five studies looking at exercising in the fasted of fed state found no evidence of a difference in body weight or composition.
 
Point 4: Rapid weight loss is best – 800 kcal

There is certainly increasing evidence that rapid weight loss is effective. In Issue 19 we introduced the DiRECT study, which successfully used a low-calorie total replacement diet (around 825-853 kcal/d) for weight loss and the remission of type 2 diabetes.

But as with all things nutrition, it is not a one size fits all – or a one diet suits all. So, while we are seeing more support for more rapid weight loss, this does not mean we throw out the steady and slow approach – such an approach will suit some people. It’s our jobs as health professionals to work with our clients to seek the best option.
 
If there is anything we’ve learnt about weight loss, it’s that there are lots of ways to lose weight. Basically, as the laws of physics demand, we need to be in negative energy balance to lose weight. And because keto is restrictive in what we can eat, most people will consume less energy compared to their habitual diets and surprise, surprise they lose weight – at least in the short-term.

Like many other diets, as people’s enthusiasm for such restrictive eating patterns wane, the weight starts to pack right back on.  
 
The key to weight loss is finding an eating plan that suits the individual – one that induces a calorie deficit. Then add in other simple advice such as choosing minimally processed foods and eating slowly.

Lots of studies highlight the importance of contact time and support. The highly intensive Look AHEAD study showed successful weight maintenance at 4 years was associated with attending more treatment sessions. This support role is where nutritionists, dietitians, and health coaches are so important.

Next up - bridging science to practice.

Best Practice

In this week's Best Practice - we recommend Michael Mosley's new diet book... just kidding Rachel!!

Instead we bring you an evidence-based summary of the long-term weight maintenance strategies in the highly successful Look AHEAD study

The Look AHEAD (Action for Health in Diabetes) study assessed the effects of an intentional weight loss programme over 8 years on cardiovascular morbidity and mortality in over 5000 overweight/obese adults with type 2 diabetes.

Year 1 of the intervention was designed to induce weight loss (> 10%), and Years 2 to 8 were focused principally on maintaining weight loss.

Lifestyle counselling was provided primarily in individual sessions to allow tailoring to specific treatment needs.

Support was provided by nutritionists, psychologists and exercise specialists. Counselling was culturally tailored and incorporated cognitive behavioural therapy, and motivational interviewing.

Individual sessions every 2 weeks:

• Individual, on-site meeting (20-30 minutes) each month
• Follow-up meeting 2 weeks later by telephone or email (up to Year 5)
• Individualised calorie goals based on desire to maintain weight, lose more (if BMI > 23), or reverse weight gain
• Encouraged to use meal replacements to replace one meal or snack per day
• Exercise > 200 minutes per week
• Monitor weight weekly or more often

Group meeting offered monthly:

• Weigh in
• Diet and activity review
• Lifestyle modification sessions

Refresher Group Campaign offered once a year

• Organised around a weight loss and/or physical activity theme
• Duration 6-8 weeks

National Campaign organised once a year

• Group challenge to meet a specific goal (e.g., losing 5 lbs) to receive small prize
• Duration 8-10 weeks

A few more points about the 8 year programme

• 90% completion rate!
• Of the participants who lost > 10% in Year 1, 39% maintained this weight loss by Year 8 and 26% maintained a loss between 5-10%
• Those who maintained the full 10% loss at Year 8 reported high levels of physical activity, reduced calorie intake and frequent monitoring of body weight