News & Blogs

Why do Diets Fails? What does the Science Say?

There are two prominent findings from all the dietary studies done over the years. First, all diets work. Second, all diets fail. What do I mean? Weight loss follows the same basic curve so familiar to dieters the world over. Whether it is the Mediterranean, the Atkins, or even the old-fashioned low fat, low calorie, all diets in the short term seem to produce weight loss. Sure, they differ by the amount – some a little more, some a little less. But they all seem to work. However, by 6 months to 1 year, weight loss gradually plateaus followed by a relentless regain despite continued dietary compliance. This occurs regardless of the dietary strategy. In the 10-year Diabetes Prevention Program, for example there is a 7 kg weight loss after one year. The dreaded plateau, then weight regain, follows. So, all diets fail.

The question is why?

Permanent weight loss is actually a two-step process. There is a short-term and a long-term (time dependent) problem. This resistance to weight loss represents homeostasis. The hypothalamic region of the brain determines the Body Set Weight (BSW). This is our fat ‘thermostat’. Insulin acts here to set BSW higher. In the short term, we can use various diets to bring our actual body weight down. However, once below the BSW, the body activates mechanisms to regain that weight. This resistance to weight loss was first demonstrated by Drs. Leibel and Hirsch in 1984. Obese persons that had lost weight require fewer calories. Their metabolism had slowed dramatically. The body is actively resisting long-term weight loss. This widely known fact has been both proven scientifically and empirically.

Imagine that you set your house thermostat low, and you are cold. You plug in a small electric heater. Soon, the house starts to warm up. Any brand of electric heater seems to work. All heaters work. This is the short-term solution to the problem. After a while, the thermostat senses that the temperature has gone up. So it turns on the air conditioning to bring the temperature back down. Eventually, after a seesaw battle, the house always wins. The temperature eventually drifts down and we are cold again. This is the long-term problem. All heaters fail. The problem is homeostasis. While we have adjusted the temperature, we have not adjusted the thermostat.

Now, let’s put this into obesity terms. High insulin levels set the BSW ‘thermostat’ at a weight that is too high. Now we decide to lose weight. Following any reasonable diet reduces weight in the short term. This is the quick fix – just like the electric heater. What happens in the long term?

The problem of insulin resistance (time dependent factors) has not been addressed. The insulin resistance keeps insulin high. The BSW is still set at a very high level. The body responds to the weight loss by raising the body weight back up. Hormonal signals of hunger are increased, compelling us to eat. If that doesn’t work, total energy expenditure (TEE) is reduced. This was exactly the experience of the participants in the Minnesota Starvation Experiment. As metabolism decreases, it becomes harder and harder to lose weight. Eventually, after a seesaw battle, the BSW wins. The end result is all too familiar – weight regain. The problem is homeostasis.

So, there are actually two separate questions to lasting weight loss. There is both a short-term and a long-term question. The short-term question is “What to Eat”. The longer-term problem is why all diets fail. This is the problem of insulin resistance and resetting the BSW. This question revolves around “When to Eat”.  While these two questions are related, they must both be addressed to develop a comprehensive solution to obesity.

Dr Nasr Al-Jafari is a Dubai-based Family Medicine Consultant and Functional Medicine Practitioner. He graduated from The University of Nottingham and completed his consultant training at The University of Manchester, UK. He has pioneered the use of obesity theory in the UAE for weight loss and type 2 diabetes reversal at DNA Health Medical Center where he is Medical Director.



Explore other newsletters

Diet’s Just Don’t Work

The multifactorial nature of obesity is the crucial missing link. There is no one single cause of obesity. Do calories cause obesity? Yes, partially. Does sugar cause

Sleep Deprivation and Obesity

Sleep is on the decline. In early 20th century people slept 9 hours/night. By 1960, Americans were averaging 8.0-8.9 hours. By the 1990’s this had

Know more about wellness

Reach to us