My question is, does this diet lead to substantial weight loss, say a 25% reduction for an obese male, without any serious adverse side affects. By serious, I mean things that would kill you. For instance a statistically significant increased risk of heart attack or cancer is a serious side affect. Also, for the purposes of this question, for a diet to "work" the weight has to stay down and not come back in 12-36 months.
There is evidence that adherents to the Atkins Diet can reduce their weight and keep it off, provided they stick to the diet.
One widely cited New England Journal of Medicine study from 2003 looked at 63 participants over one year, and found that Atkins Dieters lost weight faster initially, but slower later on. At one year, there was no significant difference between the weight loss of Atkins Dieters and conventional dieters. The authors noted that "adherence was poor and attrition was high in both groups" and called for longer and larger studies. It is worth noting, as the authors do in their Results section, that the Atkins group saw increases in HDL cholesterol (the good kind) and decreases in triglycerides (low triglyceride count is good) over most of the study.
Another study from 2003 in the Journal of Perception and Motor Skills showed that Atkins Dieters "will experience more fatigue, more negative affect, and less positive affect in response to exercise than those individuals who are not restricting carbohydrates."
These studies and a small number of other studies are discussed in a 2009 overview of the Atkin's Diet from the American Academy of Family Physicians. They conclude that the Atkins Diet can be effective, and while there are concerns about safety (most notably the risk of long-term heart disease), they assert that the evidence so far is inconclusive on that point.
The evidence that the diet is effective should not be taken as evidence that the theories behind the Atkins diet are correct, however. One researcher opined, in a WebMD article that, "No one has shown, in any studies, that anything magical is going on with Atkins other than calorie restriction. The diet is very prescriptive, very restrictive, and limits half of the foods we normally eat. ... In the end it's not fat, it's not protein, it's not carbs, it's calories. You can lose weight on anything that helps you to eat less, but that doesn't mean it's good for you."
The high attrition and low adherence mentioned in the first study also tends to support the widely held view that highly restrictive diets, like Atkins and many other diets, are difficult to maintain over the long term. Thus, while they may be effective in the short term at reducing weight, standard lifestyle changes like eating a balanced diet and exercising are likely to be superior for life-long weight loss and health.
The Atkins diet consists of 4 distinct phases. ALL (AFAIK) negative stories about it have to do with extremely prolonged adherence to the first of these, which is a diet almost completely free of carbohydrates. If you read the Atkins diet plan a bit though (just reading the basics is enough) you'll notice that this stage is recommended to last no more than 2 weeks (I think it was, been a while) unless under medical supervision. After this, carbohydrate intake is slowly increased in the followup stages, to a sustainable (but low in comparison to diets that aren't CH restricted) level.
Dr. Atkins himself lived according to his own diet for decades until he died of non-related causes that could have killed anybody.
Many advocates of other diet plans have trouble with the Atkins diet for several reasons:
- it works, longterm, if you stick to it (which can be hard, but the same is true for other diets that work longterm, they're all hard to stick to)
- it requires no large sums of money to buy special diet products (in fact it states clearly that most "diet" products are to be avoided), thus there's no sustained source of income for dietitians, diet food manufacturers, etc.
- because it works long term, you'll be less likely to be visiting that dietitian again for more diet tips. Again, they lose a steady source of reliable income.
- as it is low in carbohydrates, a good portion of the rather powerful agricultural and processed foods lobby doesn't like it. You'll be buying fewer McDonald's hamburgers, Hershey chocolate, Coca Cola, Del Monte canned pineapples, etc. etc. Those (and many other) companies don't like to see their incomes reduced by people preferring to cook their own from raw ingredients.
Overall then, there's a lot of money being spent to blacken the reputation of the Atkins diet (and others that work, but this is the one being discussed here) because it threatens people, and it's not the people following the diet.
From personal experience I know it works, and I know it's very hard to keep up long term (I've got to get restarted, couldn't keep it up for more than about 2 years), and like all diets once you stop them you indeed gain the weight lost back relatively quickly.