Sunday, January 24, 2010

For weight loss, carbs in or out?

Anyone who has lost significant weight by design will happily tell you how it was done and what they believe is the perfect diet for successful weight loss. It will always be a low calorie diet, no matter how they dress it up, although the composition of that diet is the stuff of discussion and argument.

Weight loss significant

An Australian study put 141 overweight subjects on a low kilojoule meal replacement diet (eg milkshake) for three months providing 210 kJ (500 Cals) a day. That then followed with 12 months of either a high protein or a high carbohydrate individually tailored diet. So, everyone was followed for a total of 15 months. Each diet provided the same amount of kilojoules/calories. Both groups lost an average of 16.5 kg (36 lb) in the first three months and maintained a weight loss of 14.5 kg (32 lb) twelve months later.

Heart benefits

The high protein diet provided about twice the protein of most free-living westerners, so being a low energy diet, it still meant modest servings of meat and fish. The high carb diet was closer to what most people eat when “watching their weight” (it wasn’t really high in carbs). It wasn’t just weight that changed. Bad cholesterol came down, good cholesterol went up and triglycerides came down. Blood pressure remained pretty much the same.

Calorie amnesia

The study also revealed a common phenomenon, that of under-reporting. It has been well documented that people frequently get “calorie amnesia” and forget to report exactly what they have eaten. Published data on under-reporting shows we forget 12-54% of what we eat, making it difficult to identify why weight creeps on because all you remember is the salad and fruit you eat. In this study the ladies under-reported by about one-third.

Surprisingly, the guys had much better recall with an accuracy of 99%. I say, surprisingly because under-reporting of 1% is the lowest recorded. I’m too frightened to make a gender related comment here, but you can bet that had this study been about beer, that 1% figure would have been different.

What does it all mean?

Success is only ever likely if you follow a style of eating that you are going to enjoy for the rest of your life. That might be with bread or without it. Over time, both groups began to eat more and more similarly to each other, which may partly explain why the researchers didn’t see any difference in weight loss between the two diet groups.

Those that are involved in research like this are selected because they are more motivated than the average. They also got free monthly counseling, which is not within every person’s budget. Even so, 40% of those in the study dropped out before the end of the 15 months. As you have heard me say before, losing weight is quite easy. So is gaining weight. Maintaining the weight loss is the really tough part, way beyond what most people can cope with. This study showed that it’s possible to maintain weight loss over 12 months – the type of diet didn’t make any difference.

Reference: American Journal of Clinical Nutrition 2009; 90: 1203-1214

Don't be fooled by weight loss ad

In my local paper there was an ad for a half price fat and cellulite-losing program. The moment the word “cellulite” appears the red warning light was illuminated. Reading further, I saw the word “detox”, which triggered the scam alert siren. Then the ad said that on this program you will “burn 1200 Calories in 50 minutes whilst you relax fully clothed”.

First, let me say never, ever use the word “whilst” in print. Well, when have you ever said “whilst” in your life? Imagine saying “Would you please hold my jacket whilst I go to the bathroom?” People will think you are a right twit. And they are fully justified.

Second, do you know who has ever come close to burning 1200 Calories in 50 minutes clothed? I mean properly measured, not guesswork? Tour de France cyclists climbing the Alps. They have their backside out of the saddle, legs pumping, sucking in huge volumes of air, eyes bulging, aching for the finish line. Do they look relaxed to you? During an Alps sector they can burn 7740 Cals (32,400 kJ) over six hours.

Another example. Mike Stroud once burned 11,630 Cals (48,700 kJs) in a day, about 500 Cals an hour. This is the biggest daily calorie burn ever measured in the world. Want to know how he did it? By crossing Antartica pulling a 222 kg (480 lb) sled. I met Mike in Southampton, England for a chat. I now regret not asking him how relaxing he found the three month trekking experience. He did lose 25% of his body weight and he was fully clothed, so if you answer the ad and they rug you up and check your passport before putting you on a plane heading south, well, you were warned.

Tuesday, January 12, 2010

Mental Calorie Budget

How do you control how much you eat in a world of relatively cheap food that’s easy to buy anytime of the day? You might be one of the rare folk who eat well until hunger departs, allowing your appetite to keep your weight healthy. Well done you. Most people today look at food and go through the “should I or should I not?” mental routine. Should I choose dessert or not? Have I deserved a treat? It’s a common self-justifying system employed by many.

Putting on the calorie brakes

Does giving yourself a Mental Calorie Budget (MCB) help you to control your eating when surrounded by abundant food? In theory, yes, according to research done by scientists in the US and France. They convinced one group of adults to keep a MCB on the amount of treats they would consume when offered plenty of treat opportunities over a day. As they were offered treats, they had the option to accept or reject each one.

If they had a MCB they ate much fewer treats than the control group who were not asked to have a MCB. Well it worked when done as an online exercise and only if the MCB was specific, such as “I won’t eat any treat over 100 Calories (420 kJ)”, not, for example, “I’ll try and avoid high calorie treats”.

The power of the outside voice

So, would the theory work in real life too? Let’s face it, it is easy to reject a treat that you just get to see on the computer screen. It’s a whole different story if the treat is edible and within reach. The researchers found that the MCB worked well in real life too. What was interesting was that when limits were made by an external voice (such as by a health professional) they were more effective that an internally voiced limit as you might tell yourself. This reinforces the potential benefits of advice from your doctor or dietitian. Well, for a short while at least.

Frequently stated message

If you know that you have a weakness for chocolate, biscuits or anything ending in –ccino then setting a MCB each morning as you clean your teeth may be a helpful way of restricting those foods or drinks. I suspect the message to self would have to be made every day as I can’t see a Monday message getting you through to the weekend. And, to be honest, it will only have a limited effect if you are trying to lose weight. You will need to employ other mind games (eat slowly, not buying treats in the first place etc) for the MCB to be helpful. Just remember that chocolate biscuits only have the power you give them in the first place.

What does it all mean?

When food was scarce or unpredictable, as it has been for most of human evolution, the choice was simple: eat or starve. It is no surprise that we haven’t adapted well to having an abundance of food choices close at hand. It is so easy to eat “just one more” to be sociable or get another squeeze of endorphins running around the brain sending off “oooh, yummy” feelings.

One useful message you could implant in your brain each morning is the MCB. “Yes, today I shall have only one hot chocolate (or one biscuit or one beer)”, or even telling yourself that you will eat two pieces of fresh fruit that day. A message to your brain on arising each morning could be a neat way to help control your shapeliness.

Reference: Journal of Consumer Research 2010; 37 (doi: 10.1086/6496.50)