Navigating the world of diets can make anyone’s head spin. Low-this, low-that, eat-this, but none-of-that. What works? What’s a gimmick?
With this, my goal is to help answer questions and clear up the confusion surrounding some of the most popular diet trends of the last several decades.
I’ll start with low-fat, which started somewhat of a diet revolution in the 1980s and early 1990s.
Some of the most well-known low-fat diets include the Therapeutic Lifestyle Changes Diet (or TLC, which is endorsed by the American Heart Association) and Ornish.
Low-fat diets minimize the consumption of fats—a major macronutrient—to below 35% of your daily calories. Some plans allow only 15% of your calories to come from fat sources.
Most low-fat diets emphasize lots of lean proteins (such as turkey, chicken breast, and fish), vegetables, fruits, low-fat or fat-free dairy, whole grains, nuts, and seeds. Full-fat dairy, egg yolks, and most fatty cuts of meat (such as red meat) are avoided.
A lot of early science pointed to heart benefits as a result of decreased fat and particularly saturated fat intake. But the more we’ve learned about fat in recent years, it has become clear that it was vilified based on a number of assumptions that just weren’t true.
We now know that fats that come from the right natural sources aren’t bad for you and can have an important place in your diet to prevent disease and enhance your health.
For example, unsaturated fats from sources such as avocados, nuts, olive oil, and fish are essential for proper heart function. And I wrote about this before, and I still believe that the balance of the evidence does not support all the negatively advertised effects of saturated fats on heart health. In fact, one recent meta-analysis of 21 studies found “no significant evidence for concluding that dietary saturated fat is associated with increased risk of coronary heart disease or cardiovascular disease.”1
As for weight loss, you can shed pounds by cutting out dietary fat in the short term, but long-term success is a different story. Researchers who conducted a meta-analysis on this matter wrote, “in trials lasting one year or longer, fat consumption within the range of 18-40% of energy has consistently had little, if any, effect on body fatness… Diets high in fat do not account for the high prevalence of excess body fat in Western countries; reductions in the percentage of energy from fat will have no important benefits and could further exacerbate this problem. The emphasis on total fat reduction has been a serious distraction in efforts to control obesity and improve health in general.”2
While low-fat diets have decreased in popularity as of late, many doctors still recommend them, particularly for heart health. But really, the only fat you need to eliminate from your menu is trans fat—a manmade abomination that causes a multitude of health problems. Additionally, much of the research (including studies from my own lab) reveal that you should limit your intake of pro-inflammatory omega-6 fatty acids, which primarily come from cooking oils such as soybean, corn, and vegetable oils. Otherwise, dietary fats (and especially omega-3 fats) can be a healthy part of your diet.
Low-fat diets moved to the back burner in the mid-90s while low-carbohydrate diets such as Atkins and South Beach gained a massive following.
In general, low-carb diets emphasize high protein, high fat, and low carbohydrate (and sugar) consumption—as little as 10% of your daily calories. This means no pasta, bread, processed foods, fruits, and starchy veggies (such as potatoes and carrots). Permissible foods include full-fat dairy, poultry, red meat, fish, eggs, and non-starchy vegetables.
Now, there’s a reason this extreme diet trend didn’t last long. While it is definitely not unusual to lose 10-15 pounds or more in the first few weeks of low-carb dieting, any type of plan that severely restricts any major food or macronutrient group is just not sustainable in the long run.
Not only that, low-carb diets lack fiber. Fiber is a complex carbohydrate (so it is counted as a carbohydrate) found in fruits, vegetables, whole grains, nuts, and legumes. When you consume dietary fiber, most of it passes through the intestines and is not digested. And most importantly, fiber helps to keep you regular and helps to make you feel full and satisfied after eating while reducing cholesterol levels. So remove the fiber carbohydrate and you have almost no chance of losing weight long term!
One of today’s biggest diet trends is the Paleolithic (Paleo) diet, thanks to a huge community of Crossfit athletes who preach its many benefits.
The Paleo diet consists of foods that our ancient ancestors hunted and gathered—proteins and plant-based foods such as meats and fish, vegetables, berries, seeds and nuts. However, all dairy, grains, legumes, starches, alcohol, sugar, and processed foods are eschewed. The theory is that our digestive systems were not designed to handle these types or categories of foods. It’s not have cavemen ate, so it’s not how we should eat.
Some studies indicate that a Paleo lifestyle could reduce the risk of heart disease, metabolic syndrome, diabetes, and cancer.3-4 Obviously these are great benefits.
But one downside is that research indicates Paleo dieters may have low calcium and vitamin D.5
And practically speaking, imagine your life without the occasional peanut butter sandwich, chocolate chip cookie, or glass of wine. The restrictive nature of Paleo is such a major drawback that many people have a hard time making it a long-term lifestyle unless they give themselves a “cheat day” or two to indulge in some forbidden foods.
The Mediterranean is a healthy lifestyle and eating approach that is not the least bit restrictive, and easy to follow and maintain over the long term.
Dietary staples include of fruits, vegetables, fish, nuts, seeds, legumes, whole grains, olives and olive oil, and herbs and spices. Poultry, eggs, and select dairy products are also eaten in moderation. Red wine, while not “mandatory,” is also among the items enjoyed occasionally.
Heart-healthy unsaturated fats are frequently consumed—mainly in the form olive oil, nuts, and avocados. Plus, significant levels of anti-inflammatory omega-3 fatty acids are obtained from fish.
Notably missing from this list: processed food, fatty red meats, and sweets. These foods are usually reserved for very special occasions or avoided altogether.
Overwhelming research has shown that the Mediterranean diet promotes better cardiovascular health, blood sugar control, and cognitive function. And while it’s not a weight-loss plan, you can shed weight, particularly belly fat, by adhering to it.6-9
As I’ve written before, this approach to eating is so in line with my own research and beliefs that it was the foundation of a program I developed called the Gene Smart diet. The primary difference between the Mediterranean and the Gene Smart diet is that I added additional fiber and protein-containing foods that enhance satiety and further lower inflammation, thereby placing a special emphasis on weight loss/control and reducing inflammatory diseases. (To learn more about the Gene Smart diet, read my book by the same name.)
Since the Mediterranean diet and the Gene Smart diet do not force you to give up major food groups or macronutrients such as carbohydrates and fats but help you choose the most healthy carbohydrates and fats, it’s a sustainable approach you can follow for as long as you live without getting bored of it. The Gene Smart diet is also designed for weight loss.
Choose a Lifestyle, Not a Diet
I strongly believe that when you choose to make positive changes to your diet, you should look beyond benefits such as instant weight loss and think about whether that particular eating plan is something you can adopt permanently. For that reason alone, any diet that emphasizes major restriction may not be the best way to go.
Do fat- and carb-limiting diets help you lose weight in the short term? Probably. But two, five, even 10 years down the road, will you still be following them? Probably not.
And, you will likely be much heavier. The key to success is a sustainable diet that utilizes healthy, life-giving macro- and micro-nutrients, which allows you to control your calories and lose one to two pounds a week. This is the type of diet that can be adapted into a lifestyle.
This is why eating plans such as the Mediterranean diet and the Gene Smart diet tend to appeal to the masses and benefit nearly everyone.
For more information go to GeneSmart.com
- Siri-Tarino PW, et al. Am J Clin Nutr. 2010 Mar;91(3):535-46.
- Willett WC. Obes Rev. 2002 May;3(2):59-68.
- Kowalski LM and Bujko J. Rocz Panstw Zakl Hig. 2012;63(1):9-15.
- Frassetto LA, et al. Eur J Clin Nutr. 2009 Aug;63(8):947-55.
- Jew S, et al. J Med Food. 2009 Oct;12(5):925-34.
- Esposito K, et al. BMJ Open. 2015 Aug 10;5(8):e008222.
- Psaltopoulou T, et al. Ann Neurol. 2013 Oct;74(4)580-91.
- Safouris A, et al. Curr Alzheimer Res. 2015 Jul 10. [Epub ahead of print]
Romaguera D, et al. J Nutr. 2009 Sep;139:1728-37.