Considering most queries raised through this series have been on different types of diets, this week I shall conduct a broader study of some commonly followed regimes. I have already discussed the Keto diet in an earlier article.
One of the most commonly endorsed dietary regimes is the Paleo diet. This diet is based on the concept that we should eat what our early ancestors ate i.e. before the advent of agriculture over 10,000 years back, a period which covers 99% of human history.
Broadly this involves giving up on all sugars (except some fruits), grains including wheat, milk and milk products, legumes and beans. This means that one should only eat non-starchy vegetables, organic meats, fish, some root vegetables, nuts, seeds and some fruits which are ideally low glycemic (berries, kiwi, maybe some papaya and watermelon).
Obviously, this is a very restrictive diet and hence hard to follow in the long-term, even though it is quite effective. Sticking to such a prohibitive menu is hard to follow outside one’s home: either one carries food to work or eats nothing through working hours. Going out for dinner or a party is almost a non-option, if the diet is to be strictly followed.
Vegan diets are popular as well – they are also restrictive considering they only permit ‘purist’ vegetarian stuff, disallowing the consumption of meats, eggs, fish and to make it tougher still – milk and milk products as well (butter, ghee, curd, yogurt, buttermilk or lassi etc.) So, one gets lots of vitamins, minerals, fiber, and anti-oxidants without the chemical pollutants found in meats and milk. However, one misses out on some essential fats, iron, zinc, copper, vitamin B12 and D, in addition to a deficit of high quality proteins. Moreover, one can be vegan but is permitted to eat relatively unhealthy foods – sugar, refined grains, starch, sodas, highly processed oils and veggie foods tampered with chemicals. The vegan diet works only if it a structured diet, designed to focus on healthy foods, while avoiding refined carbs.
Another diet that is making waves is the Pegan diet by Dr Mark Hyman – a healthy synthesis of the Paleo and Vegan diets – taking the best of both worlds. It involves the following the below mentioned guiding principles:
Take moderate amount of fruits
The bulk of food should come from plant sources
Limit milk and milk products
Take small to moderate amounts of any meat
Avoid gluten (i.e., wheat and wheat products)
Eat healthy fats
Take more lentils (dal)
Avoid too many beans
Eat organic foods
Again, this is a restrictive diet, but less so than both Paleo and Vegan diets, making it more acceptable in the long run.
The Atkins diet is the original low carb diet. It focusses on an unlimited intake of meats, eggs and seafood, limiting only the amount of carbs to 5% of total daily calorie intake. Modifications of this diet are the keto diet, diets allowing more carbs (up to 10% of daily calories), and a vegetarian Atkins diet.
Commonly, the advice now is to start with the Atkins 20 (only 20gm carbs per day) in the initiation phase for 2-4 weeks (which results in quite a dramatic weight loss), followed by gradual re-introduction of some carb groups, one at a time (up to a total of 40gm per day). Protein sources for vegans would be nuts, seeds, legumes, green leafy vegetables and healthy grains like quinoa, while vegetarians can take eggs, curd and cheese. It has the advantage of being filling, and not bothering with calorie count; the major disadvantage is the pain of avoiding carbs such as in desserts and snacks.
In a comparison of 4 popular diets (Atkins Traditional Low Fat Ornish and Zone Diet (A TO Z) study), the Atkins diet scored over Traditional low fat, Ornish (very low fat and low refined carb diet) and Zone diet (discussed later in the article) both in terms of the amount of weight loss, biochemical parameters such as lipid profile and a reduction of blood pressure.
The Warrior diet has only recently gained popularity in Nutrition circles. Developed by Ori Hofmekler (a former Israeli soldier), it involves fasting throughout the day (20 hours, taking only light food stuff), and eating a single, heavy meal at night (a 4-hour feeding window). It seems to overturn the entire science of Nutrition, and basically allows almost all kinds of foods if some basic rules are followed.
During the day, one can eat raw fruits, vegetables (especially green, leafy ones) and light fresh proteins (yogurt, buttermilk, eggs, nuts and seeds, protein shakes-but only one protein source per snack) with lots of water. Tea and coffee are allowed unsweetened, as are fresh vegetable and fruit juices.
Dinner is the big meal – starting with uncooked green leafy vegetables, followed by proteins (meats, fish, eggs, beans, cheese), then cooked vegetables with fat, followed by simple carbs in the end i.e. rice, potatoes, corn, quinoa, barley and presumably some wheat. He also encourages the consumption of the so-called anti-oestrogen foods like cabbage, cauliflowers, onions, garlic, citrus fruits, dairy products (from grass-fed cows / buffaloes) and chamomile, which inhibit the fat promoting oestrogenic chemicals in modern foods.
The only instruction here is to focus on eating fresh foods and to stop eating when one feels “more thirsty than hungry”. Exercise, including resistance exercise is encouraged, and a snack can be added after the workout.
This diet appears to work as the glycemic index is low, and carbs are taken only at the end of the single daily meal, when the appetite is markedly lesser and the capacity to raise blood sugar quite low due to the large amounts of low carb foods already eaten. However, there has been no clinical trial data confirming the benefits of this diet in the general population, so I am wary of advising it to everyone. It can be considered as an option by very active individuals, under medical supervision.
The Military diet was supposedly developed by the US Military for quick weight loss. This is also called a 3-day diet or the ice-cream diet, as there is a 3-day meal plan to be followed (1100-1400 calories per day), and then for the remaining 4 days in a week, one is encouraged to eat healthy. No food groups are restricted, provided calories are kept low (up to 1500 per day). These 7-day cycles can be repeated till one reaches the weight goal.
However, it appears to be more of a fad diet as the calories are too low to be maintained for a prolonged period, and the weight loss is not as much as claimed (10lbs per week). Junk foods such as ice creams are allowed once daily, if the total calories are adhered to. Probably, all the weight lost would come back once the dieter goes back to a normal diet.
Other diets that are commonly undertaken are the Zone diet (40% carbs, 30% fats and 30% proteins); the low-fat diet that almost everyone follows (and replace the fat with carbs – often leading to a rebound after some initial fat loss), the Mediterranean diet and the Keto diet (discussed earlier).
Of these, the Mediterranean diet has the maximum supporting data, especially in lowering the risk of heart disease. This is a predominantly vegetarian diet recommending fruits, vegetables, legumes, whole grains, fish, nuts, olive oil and red wine in moderation (optional), along with limiting the salt intake and allowing red meats a few times every month.
The above diets have lots of common features, but some unique aspects as well. The very fact that there are so many plans available and all of them supposedly work (while most of the urban population continues to be overweight or obese), means that they work, but not optimally or for life.
Next week, we shall discuss these aspects, and try to understand how to construct a plan that works for a lifetime.
This is a recurring column published every Sunday under the title: What is Nutrition. Next week I will do a deep-dive on "Comparing Popular Weight Loss Diet Plans Suitable For A Lifetime". Stay tuned.