Category Archives: Diet

Athletes and high carb diets: what about everyone else?

The World Health Organization predicts there will be 2.3 billion overweight adults in the world by 2015 and more than 700 million of them will be obese. Figures for 2005 show 1.6 billion adults were overweight and 400 million were obese. That’s a forty percent increase in just 10 years, at a time, where heathy living has never had a higher profile in the media. Obesity is a new problem. My grandparents generation didn’t worry about it. Of course there have always been a few fat people, not the kind of epidemic we have today. Yet there has never been so much diet advice and still people keep getting fatter and fatter. Why? One reason is this kind of thing, here’s an except from a recent article on the diet of Jessica Ennis:

What’s a typical breakfast for you?
I’ll have a bowl of Bran Flakes with fruit juice and maybe an organic flapjack or a piece of fruit.
What and when do you tend to snack on during the day?
It all depends on how long my training sessions are but I tend to have a cereal bar, banana or apple in between them.
What do you eat for lunch?
I have a ham or turkey salad sandwich and some more juice or a recovery drink.
What is your favourite dinner and dessert?
I eat a lot of red meat like beef which, as an athlete, is good for iron. So I’ll probably have chilli or lasagne or stir-fries. I always have dessert. I usually go for something chocolatey.

Nothing wrong with this diet for a full-time athlete like Jessica Ennis burning thousands of calories a week training, but how many people will be reading that and thinking, if I eat like Jessica, I’ll look like Jessica?

The truth is that there’s a world of difference between the dietary requirements of top sports people and the general population. Yes of course a premiership footballer needs a nice a nice big bowl of pasta for lunch, he’s just spent two hours running around the training pitch and is probably still recovering from running 7 – 10 miles during the weekends game. For most people living pretty sedentary lives, too many carbs are just going to make you fat.

Most people need a lot less carbs than they think.
Carbs are needed to keep up high intensity excise. So for sitting in front of the TV or wandering around the shops or the office, our bodies just don’t need them. To understand this lets compare what happens when we eat a high carb meal.

First lets look at a top athlete.
As they start to excise harder their body’s muscles can no longer provide all the energy they need aerobically. During aerobic exercise our bodies convert fat into energy, the problem is that the chemical process that takes place is quite slow and as exercise intensity increases our energy needs exceed what can be supplied aerobically. At this point we need a new (faster) fuel source. This is where the anaerobic energy pathway comes in, burning glycogen stored primarily in our muscles to create the energy needed. After prolonged anaerobic exercise our body needs to replenish the glycogen used and the only way to do this is to convert carbohydrates. However, producing energy aerobically needs uses a lot of oxygen, which is why as we exercise harder we get out of breath and as a result only very fit people can burn a significant amount of muscle glycogen. Most people can only keep this level of activity up for a short time and so are only able to burn a relatively small amount of glycogen.

What happens when the general population eat a high carb diet.
The short answer is a type 2 diabetes and an obesity epidemic. This is because as we eat a carbohydrate rich meal our body produces insulin which converts the carbs into glycogen, but if our muscles are already full of glycogen because we haven’t used it up since our last carb rich meal, then it is converted to fat and stored. This is OK, once in a while, but this process puts quite a heavy strain on our bodies, causing inflammation which in turn causes plaque to form in our hearts and arteries. Over time, if we repeatedly overload our system with carbs it doesn’t need, it initally becomes insulin resistant and then eventually develops full-blown diabetes. Of course along they way we store all that fat which makes us fat.

Now that’s a very simplistic way of looking at it, so I need to add a couple of caveats.

The first one is that glycogen isn’t just stored in our muscles it’s also stored in our liver.

The second is that what I have just described is how the body stores excess calories. If you are not meeting your daily calorie needs then much of this isn’t applicable.

The third is that our bodies will use the fuel in our bloodstream (fat and glycogen) roughly in the proportion it is available. What this means is that if you eat a sugary meal and flood your blood stream with sugar, then you will burn sugar not fat. This has big implications for people looking to lose fat, because the glucose in their bloodstream stops them burning off the fat they want to get rid of. Insulin is the body’s response to eating carbs and insulin is also the bodies most powerful storage hormone. You can’t burn fat if you have insulin in your bloodstream.

Low fat diets and athletes
The “fat is bad” message is then reinforced by athletes who by-and -large are on a low fat diets. Let me explain.

Most athletes can not afford to put on too much weight, this is pretty obvious. Most sports require either power or stamina. For example to successfully head a ball Wayne Ronney needs to be able to jump higher than the other players around him. This is of course is mainly to do with skill and timing, but also to do with his power to weight ratio. If he puts on a lot of weight he obviously can’t jump as high. For distance runners, carrying extra fat is clearly going to slow them down and be a disadvantage.

Hard training breaks down muscle. Muscle contains a lot of protein, so to rebuild muscles athletes need a lot of protein. Different studies show different recommended amounts, but the minimum would be eating 0.75 gram of protein per kilo and for power sports most experts recommend a lot more then this. So if an athlete wants to repair muscles and replenish glycogen stores they need a lot of protein and a lot of carbs. Of course they need some fat to stay healthy, but they are going to primarily eat high protein, high carb meals. Think chicken breast and pasta (the mainstay of most Premiership footballers diet). To avoid putting on weight they have to maintain a balance between calories eaten and calories burnt (just like the rest of us), so by the time an athlete eats enough protein and enough carbs they don’t leave much room for fat. In other words it’s not that they are avoiding fat, it’s that they are maximising protein and carb intake and fats get sacrificed in the process.

Low fat diets and the general population
For most people low-fat diets are bad news. Low fat nearly always means high sugar/high carb and this has several (all bad) results.

Firstly carbs interfere with the bodies normal ability to regulate food intake. On our own as humans we can’t eat too much fat without feeling sick, or too much lean protein without getting bored. Don’t believe me, try overeating on fat by eating as much butter or dripping (without any bread/carbs) as you can and see how far you get or over eating protein by eating can after can of tinned tuna or chicken breast without any mayonnaise or other sources. Cut out the carbs and it’s hard to overeat.

A standard portion of McDonald’s fries and a large coke has over 1,200 calories. That’s almost three quarters of a grown man’s daily calorie needs. It’s so easy to massively overeat on carb rich foods, but it’s almost impossible to eat too many calories once you take carbs out of the equations. Without any bread, cereal, rice or sugar 2,000 calories a day is a lot of food. Most people won’t get though it all. That’s why the Atkins’ and other low carb diets work.

Even if you do manage to eat too many calories on a high fat diet, you might get fat, but you won’t get diabetes. Diabetes is now the number one killer in the western world and is caused purely by ingesting too much sugar and not burning it off.

If we really want to eat like an athlete, what would our diet be like?

Top athletes match their dietary requirements to their daily activates very carefully. So what would a carefully matched diet look like for a man who works in an office all day, drives too and from work and spends most evenings in front of the T.V.

Lets start with calorie requirements: These are going to be approx 2,000 calories.

Next lets look at carbohydrates: He’s not going to be taking part in any high intensity excise, but under normal circumstances the brain and central nervous system needs around 100 grams of carbs a day to function.

There’s not going to be much muscle breakdown from exercise going on, but there will be some, and the bodies normal hormonal activity needs quite a lot of amino acids (the building blocks of protein). For most sedentary men this would be 50 – 70 grams of protein.

There are aprpox. 4 calories per gram of protein and carbohydrate. So using the above calculations we need around 600 calories from protein and carbs. The rest (roughly) 1,400 calories can be made up of fat. Want to know what this kind of diet looks like? If you were to eat the normal western diet, but took out three-quarters of the bread, potatoes, rice, pasta, sugary drinks and puddings. You would be pretty much there?

So if you want to keep eating like an athlete, you need to start exercising like one.


Low-fat yoghurt ‘child asthma risk’ during pregnancy

Pregnant women who eat low-fat yoghurt can increase the risk of their child developing asthma and hay fever, a study says. At the European Respiratory Society conference, researchers will suggest this could be due to an absence of protective fatty acids in yoghurt.

Read more>

More evidence of the link between food and Arthritis

More evidence that diet has a direct link with osteoarthritis.

One important contributing factor to the pathogenesis of OA is diet: nutritional deficiency and imbalance, obesity and diabetes (resulting in hypoglycaemia or hyperglycaemia) can result in metabolic and systemic disturbances that in turn increase susceptibility to OA directly due to effects on cartilage. Recent studies suggest that cartilage damage in OA occurs coincident with metabolic dysfunction, nutrient imbalance and diabetes mellitus (Rosenbloom and Silverstein, 1996; Denko and Malemud, 1999; Okma- Keulen and Hopman-Rock, 2001). Furthermore, high carbohydrate diets and generalized vitamin deficiency cause metabolic damage to cartilage (Willhelmi, 1993b). Vitamins E, B2, and C have been shown to exert an inhibitory effect on OA in animals. Chondrotoxic damage may result from food contaminants and fluoroquinolones (Stahlmann et al., 1995, 2000;Shakibaei et al., 1996; Forster et al., 1998). Equally, mineral deficiency (i.e. calcium, magnesium, zinc, selenium and boron) can provoke skeletal damage in humans and animals.


Another joint disorder, which has a dietary component, is osteochondritis dissecans (OCD). In this disorder articular cartilage fragments separate from the articular surface and break off into the joint space (Williams et al., 1998). OCD in food-producing animals is caused by over-nutrition from excess protein and carbohydrate consumption and over supplementation (Slater et al., 1992). The overwhelming majority of musculoskeletal problems in companion animals and rapidly growing food-producing animal species are linked with a possible nutritional-related aetiology.

Read the full article here.

Gluten causes intestinal damage in celiac and non-celiacs.

I’ve long thought that just Gluten may be causing damage in everyone, it’s just that in many case the damage may be below the level that can be detected clinically. Until of course it’s too late. This new study published in the Scandinavian Journal of Gastroenterology would seem to agree.


Objective. Little is known about the interaction of gliadin with intestinal epithelial cells and the mechanism(s) through which gliadin crosses the intestinal epithelial barrier. We investigated whether gliadin has any immediate effect on zonulin release and signaling. Material and methods. Both ex vivo human small intestines and intestinal cell monolayers were exposed to gliadin, and zonulin release and changes in paracellular permeability were monitored in the presence and absence of zonulin antagonism. Zonulin binding, cytoskeletal rearrangement, and zonula occludens-1 (ZO-1) redistribution were evaluated by immunofluorescence microscopy. Tight junction occludin and ZO-1 gene expression was evaluated by real-time polymerase chain reaction (PCR). Results. When exposed to gliadin, zonulin receptor-positive IEC6 and Caco2 cells released zonulin in the cell medium with subsequent zonulin binding to the cell surface, rearrangement of the cell cytoskeleton, loss of occludin-ZO1 protein–protein interaction, and increased monolayer permeability. Pretreatment with the zonulin antagonist FZI/0 blocked these changes without affecting zonulin release. When exposed to luminal gliadin, intestinal biopsies from celiac patients in remission expressed a sustained luminal zonulin release and increase in intestinal permeability that was blocked by FZI/0 pretreatment. Conversely, biopsies from non-celiac patients demonstrated a limited, transient zonulin release which was paralleled by an increase in intestinal permeability that never reached the level of permeability seen in celiac disease (CD) tissues. Chronic gliadin exposure caused down-regulation of both ZO-1 and occludin gene expression. Conclusions. Based on our results, we concluded that gliadin activates zonulin signaling irrespective of the genetic expression of autoimmunity, leading to increased intestinal permeability to macromolecules.

Read the full report here.

Ketogenic diets and physical performance

Both observational and prospectively designed studies support the conclusion that submaximal endurance performance can be sustained despite the virtual exclusion of carbohydrate from the human diet. Clearly this result does not automatically follow the casual implementation of dietary carbohydrate restriction, however, as careful attention to time for keto-adaptation, mineral nutriture, and constraint of the daily protein dose is required. Contradictory results in the scientific literature can be explained by the lack of attention to these lessons learned (and for the most part now forgotten) by the cultures that traditionally lived by hunting. Therapeutic use of ketogenic diets should not require constraint of most forms of physical labor or recreational activity, with the one caveat that anaerobic (ie, weight lifting or sprint) performance is limited by the low muscle glycogen levels induced by a ketogenic diet, and this would strongly discourage its use under most conditions of competitive athletics.

Ketogenic diets and physical performance, Stephen D Phinney.
Read the full article here

Nutrition update

I’ve not updated this for a while, so here’s the report from the 8th of June.

Make sure you get enough protein

Interesting article in Time today…

Paddon-Jones presented some interesting new data from his lab on the effect of eating protein on muscle-building in both young and  elderly study subjects. He reported that contrary to conventional wisdom, which holds that the elderly tend to lose their ability to make muscle from the protein they eat, rates of muscle building remains the same throughout life – as little as 4 oz of lean beef or chicken (which contains about 30g of protein) can boost muscle bulk by 50%.

Read the full article here…