Which Fat Loss Diet is Really Best According to Real Research

There are so many fat loss diets out there. The plethora of people, place, and thing diets all purport to be the magic bullet when it comes to fat loss and fitness. What about the “Common Sense Diet”? How would that be? In any case, according the the National Institute of Health , approximately $857 million was spent in fiscal 2014 federally funding obesity research, ranking just ahead of regenerative medicine, and behind patient safety. What did we get for so many tax dollars? Surely a few pennies dribbled into diet research?

Damn straight! Although the DES (Don’t Eat Shit) diet would seem to suffice, that’s not nearly sexy or profitable enough to start a major movement, so all the white-coated book writers slapped a name on theirs and made a fortune. That being said, which diet has actual clinical research shown to be an effective fat loss diet?

The 2014 Yale study by Katz and Meller, Can We Say What Diet is Best for Health noted “There have been no rigorous, long-term studies comparing contenders for best diet laurels using methodology that precludes bias and confounding, and for many reasons such studies are unlikely”

They did conclude that: “A diet of minimally processed foods close to nature, predominantly plants, is decisively associated with health promotion and disease prevention and is consistent with the salient components of seemingly distinct dietary approaches.” and made some specific dietary recommendations to maximize fat loss and overall health.

Strictly Limit:

  • Refined starches
  • Added sugars
  • Processed foods
  • Limit overall caloric intake


Optimize Omega-3 to Omega-6 fat ratio, with more Omega-3 fatty acids than Omega-6. This study from the Center from Genetics, Nutrition and Health notes that the average western diet has a ratio of roughly 15to1 Omega-6 to Omega-3, while the ratios closer to 1:1 are proven to reduce morbidity. (I love that word, it’s so applicable)

Emphasize whole plant foods, with or without lean meat, poultry, and seafood.

Ivy League Belly Battle?

Hardly! Harvard University diet researchers discovered nearly identical results. A Harvard University study of 120,000 people (must have self-reported; no lab that big!) revealed the foods closely correlated with

Weight Gain:

“potato chips, potatoes, sugar-sweetened beverages, and both processed and unprocessed red meats”

Weight Loss:

“vegetables, whole grains, fruits, nuts, and yogurt”

That’s certainly straight from the No Surprise Department!

Interesting Dietary Findings From the Harvard Team:

Food quality does matter. Not only is higher quality, lower processed food higher in nutrition, it tends to be lower inProtein Timing calories per volume, meaning you get full with fewer calories, and receive adequate nutrition to boot.

They also cited research that found a correlation between dietary carbohydrate’s glycemic index, protein, and weight loss/regain. Diets with predominantly low glycemic index carbs and higher protein levels not only facilitated more fat loss, but those on them were less likely to regain their weight. If this isn’t your first trip down diet lane, you know weight regain can be a hole you’re just waiting to fall into.

In the end, as a friend used to say “It ain’t no missile science”.

  • Eat high quality, minimally processed foods.
  • Low glycemic index carbs and high protein (35-40% protein if resistance training regularly)

Strictly Limit:

  • Refined starches
  • Added sugars
  • Processed foods
  • Limit overall caloric intake.

Which Commercial Diet Plans Are Closest to Scientists Recommendations?

From a pure results standpoint, a comprehensive Johns Hopkins University look at Other People’s Studies (OPS), a daunting 4,200 of them, found that some of the best known diet plans actually delivered better results. Jenny Craig and Weight Watchers both led the pack when it came to weight loss over a 12 month span. Their control was professional nutritional counseling, with “do it yourself” meal planning/preparation.

The study’s largest omission? Exercise was not factored in, but they were simply compiling data from other studies.

I compared several leading “person, place or thing” diet plans to see how they fit in with the Yale and Harvard Studies.

Diet Plan Meals Supplied Diet Style / Limits Duration Includes Exercise Rec Vegan Friendly? Cost($, $$, $$$)
Atkins Diet No, although they do sell protein bars and the like High Fat / Low Carb 2 wk 1st phase, followed by an “as long as it takes” phase Yes, vague Are you kidding??? $$
Biggest Loser No Overall balanced. Limited alcohol 12 weeks Yes, includes cardio plan and basic circuit weight training routine Somewhat, but includes lean meat protein recs in BL recipes $
Body for Life No Lower carb / Overall balanced, skewed toward higher than average protein, many small meals – Limited alcohol & caffeine 12 weeks Yes, includes high intensity cardio and weight training. Weights required for program (smile). Not so much, due to focus on animal protein recs and low carb. $$ – If using rec 3 daily Myoplex shakes
Jenny Craig Yes – Jenny Craig prepackaged meals mandatory Overall balanced, JC counselors determine calorie limits, strict adherence to JC meals for duration Unlimited Yes Not Many vegan friendly meals included from JC $$$
NutriSystem Yes – NS prepackaged meals available Overall Balanced – Lower fat, low glycemic index carbs. Unlimited caffeinated bevs and diet drinks. Unlimited Says physical activity is important for health and wellness, but doesn’t have any actual exercise. Yes, NS has vegan friendly prepackaged meals available online $$$ with NS prepackaged meals
South Beach Diet Some South Beach branded foods available Lower carb, higher protein & fiber. Especially limiting on high glycemic index carbs, but doesn’t require carb counting. Length Varies – Goal based programs. First phase is 2 weeks. Encourages aerobic and strength training, but has no plan for either. Yes, the web version does have meatless options. Not so much in the book. $$
Weight Watchers Yes Balanced, focused on fruits, non-starchy veggies, and lean protein.Their “Points Plus” system keeps you accountable. Yeah, there’s a Points Plus app Unlimited Yes, based on U.S. Department of Health and Human Services physical activity guidelines Yes, WW does have some meatless recipes. $$$, but the full “all access” program includes online meetings and tools.

Overall Diet Program Notes:

Diets relying on prepackaged food are easier and less messy than cooking your own food. That can make them easier to stay on, but they can be far more expensive. Many of these prepackaged options tend to contain more artificial ingredients, added sugar, and unpronounceables than I find acceptable. There’s no free lunch here, really.

Fat Loss Diets and exercise

While fat loss diets do work, suppementing them with high intensity exercise, especially resistance training, supercharges their effectiveness

Weight Watchers:

WW gives dieters a certain daily point total, where meals receive point totals. When you’re out of points, NO SOUP FOR YOU! Foods get points based on their protein, carb, fat, fiber , calories, and digestion ease. Lower points are better. Just plug foods into the app and see how many points you have left for the day.

Is Weight Watchers close to the Havard and Yale recommendations? Yes, it is fairly close, and researchers did show it to be effective for weight loss.

South Beach Diet:

The South Beach Diet’s moderate carb and restricted sugar, along with higher protein/fiber and healthier fats recommendations fall in line with the Harvard and Yale findings.


Plenty of pre packaged food to choose from, but long ingredients lists (what is all that stuff, anyway) are the norm, and they feature lots of artificial ingredients, synthetic nutrients, and preservatives. They also have little fiber. You are expected to augment their meals with added foods though, so careful planning can deliver the missing fiber. On the other hand, if I wanted careful planning, why am I buying prepackaged meals?

The Jenny Craig Diet:

The Jenny Craig prepackaged meals, similar to the Nutrisystem and other prepackaged diet offerings, tend to be replete with additives, artificial ingredients, low fiber, and added sugars. On the subject of added sugar, there’s plenty of it. One analysis discovered 70 grams of added sugar in a single Jenny Craig meal! OUCH! While low in calories, the low fiber content means you’ll get hungry faster than if you took a trip through the China China buffet.

Atkins Diet:

Atkins popularized low carb diets, and are they ever (low carb)! While they are low carb, they’re also low fiber and eschew any mention of fat watching. Some health authorities question your long term health on such a diet, unless careful attention is paid to what kinds of fat are eaten.

While consuming copious fats may not be heart healthy, there’s now an overwhelming mountain of evidence that lower carb diets do promote fat loss. The double blind study Optimal Macronutrient Intake Trial for Heart Health (OmniHeart) discovered lower carb diets do both; help heart health and lower Type 2 diabetes risk. They weren’t as effective as the “Eco-Atkins” diet however, where fats were from strictly vegetarian sources.

The Samaha FF, et al. randomized study “A Low-carbohydrate as Compared with a Low-fat Diet in Severe Obesity”, published in the New England Journal of Medicine in 2003, found participants on the restricted carb diet lost a hefty 304% more weight than those on the restricted fat diet, while improving insulin response, lowering blood triglycerides, and dropping fasting blood sugar levels.

Remember too, that not only is fat more than twice the calories per mass of carbs and protein, it uses less energy to digest also. If you work less to digest, you’re using fewer calories and keeping more.

Biggest Loser Diet:

The BLD focuses on a balanced diet, moderate calorie restriction, and plenty of good, old fashioned exercise. Does it work? Hell, yes! Imagine that? Hard work and a balanced diet with fewer calories makes you lose weight. Whodda thunk it? Many dieters find this diet somewhat easier to follow because it doesn’t eliminate entire macro-nutrient classes i.e. you can still eat carbs, fat, and protein, although in balanced proportions.

The Biggest Loser Diet has see some changes since the first version debuted back in 2005, with the latest “Biggest Loser: The Weight Loss Program to Transform Your Body, Health and Life “ (follow that link to get it on Amazon) released in 2013. As the show’s participants and millions of viewers have discovered, it does work, extremely well, although some may balk at transforming their lifestyle with athlete-level workout programs.

No pain, no gain? Perhaps, but the diet alone is well worth a look, even if you only did a dumbbell circuit training program 3 days a week. In fact, that would be an excellent way to transform your body by losing fat and gaining muscle, especially if you’ve never trained before.

One thing I love about the diet is the food journal requirement. It’s research-proven weight loss strategies like this which make it so effective, outside of simply transforming one’s diet.

The Biggest Loser Diet downside? You’ll have to learn your way around both the kitchen and your market’s produce section, two places many folks don’t spend much time if they’re battling a weight problem. Research has proven a direct correlation between weight gain and restaurant meals. I can back that one up, especially if those restaurants have drive through windows! It’s only common sense, really.

Macro-Nutrient Balance on Commercial Weight Loss Diets

One thing to note is that the recommended diet macro-nutrient balance in most commercial diets and those based on government recommendations is for the average person, not hard training individuals or athletes. If your average day consists of grabbing your computer bag, jumping in your BMW, and heading down the 405, followed by a short sprint from the parking garage to your office, those are probably spot on.

On the other hand, if that sounds like you, but your detour past the gym for 30 minutes of HIIT cardio work, and stop by again on the way home for an intense back, bi, and leg workout, after which you have dinner, and head down to the court for a hard core pick-up game, you should probably shift your diet to include more protein. I am a strong proponent of primarily low-glycemic index carbs as well, although I’m hardly a medical or dietary professional, and I’ve never seen a script, cameras, or stage lights.

The Bottom Line – Which Commercial Fat Loss Diet is Really Best?

The thing is, you can lose fat on any of them. Exercise and restrict caloric intake and the fat drops like a wounded bomber. On the other hand, those with added sugar and a plethora of added ingredients that wold make Mr. Wizard blush….. well, they don’t make my list of recommended diet plans. Sure, they’re easy, but they’re also are expensive. From my perspective, they’re also nowhere near as healthy as making real, whole food meals yourself. Not a chef? Neither am I, but guess what? Your body doesn’t care! Anyone can learn healthy meal prep basics so you can follow the other diets. That’s what YouTube’s for.

Have you tried a commercial fat loss diet? Which one and how did it work? Let the gang know……