Diet Review—Paleo Diet

The Paleolithic (Paleo) diet is based on a simple premise: Did cavemen eat it? If not, we shouldn’t either.

Put another way, the Paleo diet consists of foods that our ancestors hunted, fished or gathered in the pre-agricultural era—animal proteins (meat, fish and some poultry), vegetables, berries, seeds and nuts. Most conspicuously missing from this list: all dairy, grains, legumes (like peanuts and soy), starches, alcohol, sugar and processed foods.

Instead of cow’s milk, the Paleo diet “allows” you to consume coconut or almond milk, and if you want to bake, you can improvise by using almond flour. But, by and large, the emphasis remains on proteins and plant-based foods.

Why would anyone want to restrict all these food groups? Well, the theory behind Paleo is that our digestive systems were not designed to handle the types of foods that have become staples in our diets over the past few thousand years. And perhaps Paleo enthusiasts have a point.

After all, when humans stopped being hunters/gatherers and became farmers, overall health took a nosedive. In fact, obesity, diabetes and heart disease rates skyrocketed in the 20th century, when refined grains, dairy-based foods and processed sweets became dietary staples.1

These diseases aside, eating a Paleo diet would likely benefit those who have intolerances or allergies to grains, gluten and/or dairy or gastrointestinal problems (which often are caused by sensitivities to the grains or dairy).

Conditions Supported by the Paleo Diet

  • General health
  • Blood sugar
  • Heart health

What Does the Research Say?

General Health

According to a study published in 2012, researchers found that eating a Paleo/hunter-gatherer diet had significant benefits across a wide range of conditions.2

Researchers compared the Paleo diet with a typical Western diet and found that the Paleo contained more proteins and long-chain polyunsaturated fatty acids, and less linoleic acid. Additionally, they found that a Paleo diet may reduce the risk of heart disease, metabolic syndrome, type 2 diabetes, cancer, acne vulgaris and myopia (nearsightedness).

Plus, researchers found that eating Paleo also held promise when it came to changing critical biomarkers, including weight, waist circumference, C-reactive protein (marker for inflammation), glycated hemoglobin (HbAlc) (a blood sugar marker), blood pressure, glucose tolerance, insulin secretion, insulin sensitivity and cholesterol numbers.

Blood Sugar

Researchers at the University of California San Francisco have concluded that a Paleolithic (Paleo) diet improves several health factors in patients with diabetes.3

In this study, 14 participants with type 2 diabetes consumed a Paleo diet, while another 10 people followed recommendations by the American Diabetes Association (ADA), which emphasized moderate salt intake, low-fat dairy, whole grains and legumes.

After just 14 days, the Paleo dieters had far better glucose control and cholesterol readings than the ADA group. Furthermore, those following Paleo who also battled severe insulin resistance saw significant improvement in insulin sensitivity. The ADA group did not.

In conclusion, the researchers stated, “Even short-term consumption of a Paleolithic-type diet improved glucose control and lipid profiles in people with type 2 diabetes…”

Similarly, a study published in 2009 found that eating Paleo improved a number of diabetes-related biomarkers, as well as risk factors for metabolic syndrome.4

In this outpatient study, researchers had nine healthy volunteers eat their normal diet for three days, then three ramp-up diets that had increasing amounts of potassium and fiber for the next seven days, then a Paleo diet for 10 days. They tested all participants at the beginning and end of the study for the following biomarkers:

  • Blood pressure
  • 24-h urine sodium and potassium excretion
  • Glucose and insulin levels
  • Insulin sensitivity
  • Triglyceride and cholesterol levels

At the end of the 20 days, researchers saw a significant decrease in blood pressure, insulin levels, total cholesterol, LDL cholesterol and triglycerides. In fact, eight of the nine participants enjoyed “consistently improved status of circulatory, carbohydrate and lipid metabolism/physiology.”

Researchers concluded, “Even short-term consumption of a paleolithic type diet improves BP and glucose tolerance, decreases insulin secretion, increases insulin sensitivity and improves lipid profiles without weight loss in healthy sedentary humans.”

Finally, a study published in 2007 compared a Paleo diet to the Mediterranean diet in 29 people with ischemic heart disease, as well as either glucose intolerance or type 2 diabetes.5

Researchers found that, after 12 weeks, those in the Paleo group saw a 26 percent decrease in glucose levels, compared to just seven percent in the Mediterranean group. The Paleo group also enjoyed greater improvements in waist circumference and insulin levels.

Researchers concluded, “A Paleolithic diet may improve glucose tolerance independently of decreased waist circumference.”

Heart Health

A study published in June 2015 suggests that the Paleolithic (Paleo) diet may improve cholesterol levels to a better extent than a traditional heart-health eating plan.6 This is particularly interesting because the Paleo diet flies in the face of conventional diet recommendations aimed at lowering cholesterol and enhancing heart health—namely diets low in fat and high in whole grains.

In this study, researchers hypothesized that a grain-free Paleo diet would lead to weight loss and a healthier cholesterol profile compared to a grain-based diet. Twenty volunteers (10 male and 10 female) aged 40 to 62 with high cholesterol (unmedicated) took part in the study. They adhered to a traditional heart-healthy diet for four months, followed by a Paleo diet for four months.

Results showed that four months on the Paleo diet significantly lowered total cholesterol, LDL (“bad”) cholesterol and triglycerides, while increasing beneficial HDL cholesterol, relative to both baseline and the low-fat, whole-grain diet.

The researchers stated, “Paleolithic nutrition offers promising potential for nutritional management of [high cholesterol] in adults whose lipid profiles have not improved after following more traditional heart-healthy dietary recommendations.”

How to Go Paleo

To “go Paleo,” focus on foods that our ancestors hunted and gathered in the pre-agricultural era—animal proteins (meat, fish and some poultry), vegetables, berries, seeds and nuts. Avoid all dairy, grains, legumes (like peanuts and soy), starches, alcohol, sugar and processed foods.

Also, since the game our ancestors hunted and fished was wild (obviously) rather than farmed, you’ll want to always opt for wild, free-range or grass-fed beef and free-range poultry or wild-caught fish.

Additionally, research has found that the Paleo diet is low in a few critical nutrients—mainly calcium and vitamin D1—so be sure to supplement with these to nutrients in particular. Aim for 200 mg of calcium and 2,000 IU of vitamin D3 daily.


  1. Jew S, et al. J Med Food. 2009 Oct;12(5):925-34.
  2. Kowalski LM and Bujko J. Rocz Panstw Zakl Hig. 2012;63(1):9-15.
  3. Masharani U, et al. Eur J Clin Nutr. 2015 Apr 1.
  4. Frassetto LA, et al. Eur J Clin Nutr. 2009 Aug;63(8):947-55.
  5. Lindeberg S, et al. Diabetologica. 2007 Sep;50(9):1795-807.
  6. Pastore RL, et al. Nutr Res. 2015 Jun;35(6):474-9.

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