Thursday 17 August 2017

Six reasons why you're not losing weight

Our resident dietitian Orla Walsh explains why some of us find it impossible to shift weight - no matter what we do

Image: Getty
Image: Getty
In theory weight loss should be simple
Dietitian Orla Walsh

There are many people out there who are trying to lose weight but can't.

Adherence to a weight loss plan is a significant factor in weight loss success which is backed up by research as well as common sense. It's true that some people keep inaccurate food diaries, and aren't always forthcoming, some people are 100pc honest to themselves and to those helping them to lose weight.

They are eating healthfully, exercising regularly and the number on the scale isn't playing ball. There is a growing level of research looking into this common complaint. 

In theory weight loss should be simple and achieved with a calorie deficit. It is a lot of the time, but not all of the time. For example:

1 One fundamental problem is that calculating the energy deficit needed for an individual to lose weight depends on accurate calculation of how many calories that person needs to maintain their current body weight. There are no methods that will do this with reasonable precision outside of a research setting.

2 It appears to be important when we eat the bulk of our calories with the first half the day appearing to be a better choice than the second half. So timing comes into play, not just the overall number of calories eaten.

3 It's not only important to look at when we eat our calories, but where the calories are coming from. It appears important to examine when we eat calories from the particular food groups, which needs to be tailored to the person's natural body type, exercise, conditions and diseases.

4 The next interestingly detail regarding the different food groups is that there is a difference in the amount of calories that are used up using the different food groups. With each food group the body needs to ingest, digest, absorb, metabolism, store or use it. It takes calories for this process to occur. When the body uses energy or burns calories, the energy is released as heat. This is called 'Diet Induced Thermogenesis' and is why Joey in Friends suffered from 'meat-sweats' after a large protein rich meal. Not only is there twice as many calories in a gram of fat when compared to a gram of protein, it also takes more calories to use protein than fat.

5 Once we consider these factors we need to then consider the foods that we are eating. Interestingly we don't actually absorb 100pc of the calories that we eat. Nuts are a perfect example of this as some of their calories will pass through our gut and into our toilet bowl unused.

Weight loss diets are a bit like a pharmacist suggesting a drug for a medical condition. There's no one drug, at one dose, that works for everyone with a given health condition, so we cannot suggest the same for diet. Unfortunately the way that a lot of research is conducted is by looking at weight loss in a bunch of randomly picked people while they follow one diet, delivered one way. We therefore may miss out on the true success rate of a particular dietary intervention because it wasn't the correct fit for all the randomly picked people.

6 There are other science-based reasons why someone may be experiencing resistance to weight loss. As with all chronic diseases, and obesity, weight loss resistance is multifactorial. However one big concern is that dieting damages the metabolism.

A good example of this is seen of extreme weight loss shows. A study looked at the long-term changes in body composition and resting metabolic rate (RMR) in participants of The Biggest Loser, a weight loss television show. Your body composition looks at how much of you is muscle and how much of you is fat. Your resting metabolic rate is a way of calculating your daily calorie budget. Body composition was measured using the gold standard method of a DEXA scan while RMR was determined by a reliable method called indirect calorimetry. They were then measured again at the end of the 30 week competition and six years later. They looked at the amount the metabolism adapted due to the weight loss process. They took into consideration the natural adaptation that would occur due to the change in body composition and age, as our metabolism generally decreases with loss of muscle and during the aging process.

Of the 16 Biggest Loser competitors, 14 participated in the full study. Weight loss at the end of the competition was an average of 58.3kg. RMR decreased by an average of 610 calories per day. After 6 years, 41kg of the lost weight was regained, while the average RMR was about 704 calories below starting levels per day. Metabolic adaptation was deemed to be about 499kcal. Basically, the participants needed to reduce their dietary intake by 500kcal per day in order to maintain their weight and keep the weight they lost off. Not only does this make maintaining their weight loss more challenging, but also further weight loss.

This is why exercise is fundamental in helping people maintain their weight and in keeping the weight they have lost off. Slow steady weight loss is often encouraged over quick extreme weight loss in a bid to preserve the metabolism and complications from the process.

5 tips for weight loss

1 Drink a glass of water before every meal

2 Reduce the speed at which you eat with a simple '10' rule

• bites should be the size of a 10 cent coin

• each mouthful needs to be chewed at least 10 times

• wait 10 seconds before you take the next bite of food

3 Each meal should contain at least 2 different colours of fruit or vegetables

4 Ensure there is a rich protein source at every meal

5 The more you move the more carbohydrate you need, the less you move the less carbohydrate you need. Tailor your intake!

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