Idai Makaya interviewed elite fruitarian athlete Michael Arnstein in June 2010. In this frank and often revealing video interview the controversial American distance runner shared his honest views on how he believes fruits can be used to improve general health and physical performance. In the discussion Arnstein endeavours at all times to qualify his dietary beliefs in a rational way. He goes as far as to suggest that we can all get by and stay healthy eating fruits alone!

Michael Arnstein has an interesting perspective on food - and on diet - and although you may not agree with all his views, many of them are still pertinent to people with more diverse diets and parts of his dietary strategy or philosophy can be applied by almost anyone to improve their health and physical performance.

Michael Arnstein eats mainly fruits (and small amounts of vegetables) and has done so for a number of years. He says he's on "a journey of discovery" which has seen him set personal best after personal best in marathons and ultramarathons - winning some big races along the way.

Arnstein appears to be healthy and extremely productive, telling me: "I run a business with 20 full-time employees, I have 3 kids (young) and I'm married. I try to run 4 hours a day lately..."

Not what you'd expect from a man who's unhealthy or malnourished. Could there be more to this - and what does it already tell those of us who use part-time fruit diets, such as fruit fasting (or those who simply eat a high volume of fruit in their diets)?

I'm well known for promoting the value of a part-time 'fruit diet' in the The Handbook of Intermittent Fasting and I also espouse the advantages of regular fruit-fasting and part time fruit-based detox dieting for calorie restriction (alongside periods specified for eating other types of calories) - but even compared to the most rigid intermittent fasting standards or protocols Mike Arnstein's frutarian dietary practices are somewhat extreme.

For clarity, I do not personally endorse a full-time 'fruit-only' approach to diet, although I do lean towards making raw fruits and vegetables a significant proportion of ones entire diet. Fruitarians have been around in various guises for a very long time so I acknowledge the dietary approach can work for some people. What is new about Michael Arnstein is the fact that he is a hard-training top athlete - probably the first to show that fruitarianism can work even for very active individuals.

However, this does not signify that this diet would suit all types of athlete (or even all endurance athletes and runners) and I advise anyone who is drawn towards this dietary approach to study it thoroughly and to gather as much information about following it as is possible - before trying it. At this stage I am not in a position to say definitively if it is (or isn't) a viable option for one's full lifetime.

Many health-conscious people (athletes, especially) are interested, curious or perhaps even worried about the implications of following a frutarian diet like Mike Arnstein's; so I felt that rather than ignore the 'controversy' (and allow it to drip-feed into society in a totally untested and unregulated manner) I'd instead tackle the issue head-on and in the public eye - so that people can make up their own minds, based on coherent debate and discussion.

When challenging new frontiers, unfortunately, the 'pioneers' are often forced to go by instinct and to go on faith and intuition alone. The disciplines of Sports Nutritional Science and General Dietetics were founded in this way and, unfortunately, the early adopters of advanced nutritional and training practices often will not yet have much solid evidence to back their theories.

Michael Arnstein claims to be one such revolutionary and pioneer. He follows an eating style sometimes referred to as "30-Bananas-a-Day" or "80/10/10rv" or "811rv" in vegan and fruitarian circles. In this series of video interviews he explains his dietary concepts and tells us why he follows them. The questions covered in each video in the interview are outlined below.

The accompanying video interviews contain Michael Arnstein's answers to the specific questions I have posed below. Although Mike's slight mis-pronunciation of my name in the video is forgiven (as we've have not actually met in person!) I hope I've not been lenient when covering such a delicate and important topic and my aim certainly was not to make it easy for him in this interview! 

Why not make up your own mind and view the video interviews yourself...

The Questions in relation to each video are listed below and each video is a stand-alone interview; so you can view just the parts which are of most interest to you - or you can view all seven parts in sequence (total running time is about 50 minutes):

Part I:

Mike, what is your main philosophical reason for using and promoting a fruit-only diet?

Why are you so passionate about it and why do you try so hard to 'spread the word' - so to speak?

Do you acknowledge any potential risks with regard to malnutrition, etc - if your diet is not followed correctly?

How do you suggest that users of a fruitarian diet ensure they are not at any risk when following such a diet?

I don't know if you have any kids Mike, but if or when you do would you 'impose' this diet on them or encourage them to follow it? Do you think this diet is suitable for children (and if so, from what age)? If not, why is it safe for long term adult use - but not for children?

Part 2:

What is the longest spell that you know of for anyone following the exact same diet that you use and sticking to it - is it decades?

Part 3:

Are you an 'anomally'? Is it just a freak occurrence that you are doing so well on a fruit-only diet? Do you know of any other athletes, anywhere else in the world, who are excelling on a fruit-only diet? If you do know of specific examples, please share them - and if you don't please explain why you think your own success is specifically related to your diet (and not just to you as an individual)?

Part 4:

There is an 'elephant in the room' when we talk of your running performances and diet - are you certain that your current performances are a true reflection of your full athletic potential (or is there a real possibility that you have improved because your diet has gone from a really poor one - by your own admission - to a somewhat better one)?

Could there be a possibility that if you added just meat to your current diet you would get even faster - maybe become a 2:10 marathoner? This is a really crucial question in relation to 'selling this lifestyle' and if you only answered one of my questions this would be the most important.

Do you know the nutritional content of your current diet and how that compares to so-called recommended daily allowances?

Part 5:

How do you monitor your health to be sure you are not developing any underlying nutritional issues or deficiencies on this 'new' (to you) diet?

You can eat up to 40 bananas daily - do you add anything else to that, typically (oranges, apples, pears, etc)?

For less active people, how would you reccommend they use this diet - since they will not need as many calories as you and it could well be that this diet only works for you because you eat so much low nutrient food that the totals build up to acceptable levels? This is another crucial question for readers.

What would you estimate your total calorie intake to be and how does that compare to other top marathon runners' diets.

Part 6:

Do you ever get cravings? I personally advise people who use intermittent fruit fasting that the fruit fasting actually purges cravings if you use the right fruits, alongside good water intake, but in my diet people go back to other nutrients regulalry and intermittently - you never alter your diet from fruits.

Does your diet ever get boring? Please be honest!

How well do you think people would fare on a fruitarian diet if their goals related to becoming stronger - or getting bigger muscles - rather than just endurance? This is another crucial question.

Do you use any supplements at all? Have you done so in the past?

Part 7:

What is your training programme like? How often in a single day do you run, typically? Do you use any other conditioning exercises?

Are you looking to become a full-time ultra marathon runner - or will you keep going at the 'shorter' distances until you think you have realised your true maximum speed potential?

What's next for Mike Arnstein and is there anything you would like our readers to know about that you are involved in - or that I have not asked about?